Updated on 2023/09/11
Doctor of Engineering （ 1989.3 The University of Tokyo ）
Space propulsion, Compressible fluid dynamics, High-enthalpy flow, Shock wave, Plasma, Laser, Supersonic flow
Others / Others / Fluidics
Others / Others / Aerospace Engineering
Application of highly-repetitive pulse laser to aerospace engineering
Non-chemical space propulsion
Study on sonic boom
Nagoya University Director
2019.4 - 2022.3
Professor, Department of Aerospace Engineering, Nagoya University Professor
2006.4
Country：Japan
Professor, Institute of Fluid Science, Tohoku University Professor
2003.3 - 2006.3
Country：Japan
Associate Professor,Institute of Fluid Science, Tohoku University Associate Professor
1991.7 - 2003.2
Country：Japan
Research associate, Department of Aeronautics, Nagoya University Assistant
1989.4 - 1991.6
Country：Japan
The University of Tokyo Graduate School, Division of Engineering Aeronautics
1986.4 - 1989.3
Country： Japan
The University of Tokyo Graduate School, Division of Engineering Aeronautics
1984.4 - 1986.3
Country： Japan
The University of Tokyo Faculty of Engineering Department of Aeronautics
1979.4 - 1984.3
Country： Japan
International Shock Wave Institute
2013.5
アメリカ航空宇宙学会
日本衝撃波研究会
レーザー学会
日本流体力学会
日本機械学会
日本航空宇宙学会 理事（編集担当）
火薬学会
日本工学アカデミー
ISBEP (International Symposium on Beamed Energy Propulsion) Award
2008.11 American Institute of Beamed Energy Propulsion
日本航空宇宙学会論文賞
1999.4 日本航空宇宙学会
日本流体力学会竜門賞
1998.2 日本流体力学会
トーキン科学技術振興財団 研究奨励賞
1992.3 トーキン科学技術振興財団
Local geometry of a weak normal shock wave interacting with turbulence Reviewed
Amane Kusuhata , Kento Tanaka , Tomoaki Watanabe, Koji Nagata,and Akihiro Sasoh
Physics of Fluids Vol. 35 ( 086110-1 ) page： 086110-14 2023.7
Investigation on Applying an InGaN Photocathode with Negative Electron Affinity for Electric Propulsion Reviewed
Yusuke Inoue, Tomohito Nishitani,Anna Honda, Daiki Sato, Haruka Shikano, Atsushi Koizumi,Yoshio Honda, Daisuke Ichihara, Akihiro Sasoh
Trans. Japan Soc. Aero. Space Sci. Research Note Vol. 66 page： 10 - 13 2023.1
Petal formation law in a cellophane diaphragm subjected to a pressure difference Reviewed
Gaku Fukushima, Jun Hagiwara, Yusuke Nakamura, and Akihiro Sasoh
PHYSICAL REVIEW E Vol. 106 page： L043001-1 - L043001-5 2022.10
Laser ablation induced impulse study for removal of space debris mission using small satellite Reviewed
Katsuhiko Tsuno/ Satoshi Wada· Takayo Ogawa· Norihito Saito· Tadanori Fukushima/Toshikazu Ebisuzaki/Yusuke Nakamura · Akihiro Sasoh
Applied Physics A Vol. 128 page： 932 2022.9
Numerical and experimental study on the behavior of vortex rings generated by shock-bubble interactions Reviewed
Keiichi Kitamura, Zhaogeng Yue, Takeshi Fujimoto, Hiroki Asai, Akiya Kubota, Manabu Myokan, Daisuke Ichihara, and Akihiro Sasoh
Physics of Fluids Vol. 34 page： 046105-1 - 046105-14 2022.4
Geometrical matching in remote in-tube shock compression by an unsteady jet Reviewed
D. Ichihara· D. Kuwabara · D. Moriyama· Y. Nakamura · A. Iwakawa· A. Sasoh
Vol. 32 page： 373 - 381 2022.3
Transition to Weak-Shock Solution Around Centerbody Using Laser Energy Deposition Reviewed
Hiroki Asai, Yusuke Nakamura, and Akihiro Sasoh
AIAA JOURNAL 2022
Electrostatic-magnetic hybrid ion acceleration for high-thrust-density operation Reviewed International journal
Ichihara D., Nakano R., Nakamura Y., Kinefuchi K., Sasoh A.
JOURNAL OF APPLIED PHYSICS Vol. 130 ( 22 ) 2021.12
Numerical Investigation of a Ballistic Range Free Flight Model Reviewed International journal
Mahomed I, Roohani H., Skews B. W., Gledhill I. M. A., Yamashita Y., Fujiwara H., Suzuki T., Iwakaka A., Sasoh A.
INTERNATIONAL JOURNAL OF AERONAUTICAL AND SPACE SCIENCES Vol. 22 ( 6 ) page： 1293 - 1301 2021.12
Energy conversion efficiency of electrical exploding foil accelerators Reviewed International journal
D. Ichihara, G. Fukushima, D. Kuwabara, and A. Sasoh
AIP Advances Vol. 11 ( 9 ) 2021.9
Losing the shock wave front profile due to interaction with turbulence Reviewed International journal
Fukushima Gaku, Wei Jiaxi, Ogawa Shingo, Hagiwara Jun, Nakamura Yusuke, Sasoh Akihiro
FLUID DYNAMICS RESEARCH Vol. 53 ( 2 ) 2021.4
In-tube shock wave compression by piston effect of unsteady jet Reviewed
Daisuke KUWABARA, Hirokatsu KAWASAKI, Akira IWAKAWA, Akihiro SASOH
Mechanical Engineering Journa Vol. 17 ( 3 ) 2021.4
Impacts of grid turbulence on the side projection of planar shock waves Reviewed International journal
Fukushima G., Ogawa S., Wei J., Nakamura Y., Sasoh A.
SHOCK WAVES Vol. 31 ( 2 ) page： 101 - 115 2021.3
Speckle beam-oriented schlieren technique Reviewed International journal
Nakamura Yusuke, Suzuki Takumi, Kinefuchi Kiyoshi, Sasoh Akihiro
EXPERIMENTS IN FLUIDS Vol. 62 ( 1 ) 2021.1
Coupling analysis of unsteady aerodynamics and vehicle behavior with road input: Modeling and verification in road tests Reviewed International journal
Maeda Kazuhiro, Tsubakino Daisuke, Hara Susumu, Sasoh Akihiro
MECHANICAL ENGINEERING JOURNAL Vol. 8 ( 4 ) 2021
Thrust Density Enhancement in an Electrostatic–Magnetic Hybrid Thruster Reviewed International journal
Daisuke Ichihara, Koichiro Oka, Ayumi Higo,Yusuke Nakamura,Kiyoshi Kinefuchi,and Akihiro Sasoh
JOURNAL OF PROPULSION AND POWER Vol. 37 ( 6 ) page： 973 - 976 2021
Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests Reviewed
Vol. 17 ( 5 ) 2020.9
Influence of cellophane diaphragm rupture processes on the shock wave formation in a shock tube Reviewed International journal
Gaku Fukushima, Takahiro Tamba, Akira Iwakawa, Akihiro Sasoh
Shock Waves Vol. 30 ( 5 ) page： 545 - 557 2020.7
Application of laser energy deposition to improve performance for high speed intakes Reviewed
A. Russell, M. Myokan, H. Bottinib, A. Sasohb, H. Zare-Behtasha and K. Kontis
Propulsion and Power Research Vol. 9 ( 1 ) page： 15 - 25 2020.3
Repetitive Energy Deposition at a Supersonic Intake in Subcritical and Buzz Modes Reviewed International journal
Manabu Myokan, Akiya Kubota, Akira Iwakawa and Akihiro Sasoh
AIAA Journal Vol. 58 ( 1 ) page： 107 - 117 2020.1
High-Specific-Impulse Electrostatic Thruster with Argon Propellant Reviewed International journal
Daisuke Ichihara, Toshihiro Matsuba, Akira Iwakawa, and Akihiro Sasoh
Journal of Propulsion and Power Vol. 36 ( 2 ) page： 256 - 263 2020
Central and External Cathode Operations in a Diverging-Magnetic-Field Electrostatic Thruster Reviewed International journal
D. Ichihara, Y. Nakagawa, A. Iwakawa and A. Sasoh
Journal of Propulsion and Power Vol. 36 ( 1 ) page： 68 - 77 2020
Boundary Effect on the Laser-ablation Impulse Characteristics of a Flat-Head Cylinder Reviewed International journal
Yusuke KATAGIRI, Daisuke ICHIHARA, Hisashi TSURUTA, and Akihiro SASOH
Transactions of The Japan Society for Aeronautical and Space Sciences Vol. 63 ( 3 ) page： 109 - 112 2020
Sunflower Effect: Enhancement of laser-pulse-induced impulse in the beam incident direction due to surface undulation Reviewed International journal
Yusuke Katagiri and Akihiro Sasoh
Physica Scripta Vol. 94 ( 8 ) page： 085004 2019.8
Experimental investigation of the interaction of a weak planar shock with grid turbulence in a counter-driver shock tube Reviewed International journal
Takahiro Tamba, Gaku Fukushima, Masaya Kayumi, Akira Iwakawa and Akihiro Sasoh
Physical Review Fluids Vol. 4 ( 7 ) page： 073401 2019.7
Electrostatic-magnetic-hybrid thrust generation in central-cathode electrostatic thruster (CC-EST)
Akihiro Sasoh , Hayato Kasuga, Yoshiya Nakagawa, Toshihiro Matsuba, Daisuke Ichihara, and Akira Iwakawa
Acta Astronautica Vol. 152 page： 137 - 145 2018.11
Amplification and attenuation of shock wave strength caused by homogeneous isotropic turbulence
Tanaka K., Watanabe T., Nagata K., Sasoh A., Sakai Y., Hayase T.
PHYSICS OF FLUIDS Vol. 30 ( 3 ) 2018.3
Rapid distortion theory analysis on the interaction between homogeneous turbulence and a planar shock wave Reviewed International journal
T. Kitamura, K. Nagata, Y. Sakai, A. Sasoh and Y.Ito
Journal of Fluid Mechanics Vol. 802 page： 108 - 146 2016.9
Electrostatic ion acceleration across a diverging magnetic field Reviewed International journal
D. Ichihara, A. Uchigashima, A. Iwakawa, A. Sasoh
Applied Physics Letters Vol. 109 ( 5 ) page： 053901 2016.8
Moderation of near-field pressure over a supersonic flight model using laser-pulse energy deposition Reviewed International journal
D. Furukawa,Y. Aoki, A. Iwakawa,A. Sasoh
Physics of Fluids Vol. 28 ( 5 ) page： 051701 2016.5
Anode Geometry Effects on Ion Beam Energy Performance in Helicon Electrostatic Thruster Reviewed International journal
Akira Uchigashima,Teruaki Baba,Daisuke Ichihara,Akira Iwakawa,Akihiro Sasoh,Takuya Yamazaki,Shota Harada,Matsutaka Sasahara,Tomoji Iwasaki
IEEE Transactions on Plasma Science Vol. 44 ( 3 ) page： 306 - 313 2016.3
Field experiment of blast wave pressure modulation past a turbulent flow Reviewed International journal
Tamba Takahiro, Furukawa Daiki, Aoki Yuma, Kayumi Masaya, Iwakawa Akira, Sasoh Akihiro, Matsunaga Takehiro, Izumo Mitsuo, Sugiyama Yuta, Matsumura Tomoharu, Nakayama Yoshio
SCIENCE AND TECHNOLOGY OF ENERGETIC MATERIALS Vol. 77 ( 3-4 ) page： 91 - 97 2016
RAMAC25 Reviewed International journal
Sasoh Akihiro
HYPERVELOCITY LAUNCHERS Vol. 10 page： 205 - 216 2016
Laser Focusing Reviewed International journal
Sasoh Akihiro
EXPERIMENTAL METHODS OF SHOCK WAVE RESEARCH Vol. 9 page： 99 - 108 2016
Counter-Driver Shock Tube Reviewed International journal
T.Tamba, T.M.Nguyen, K.Takeya, T.Harasaki, A.Iwakawa, A.Sasoh
Shock Waves - An International Journal on Shock Waves Vol. 25 ( 6 ) page： 667 - 674 2015.11
In-Tube Catapult Launch from Rectangular-Bore Aeroballistic Range Reviewed International journal
Akihiro Sasoh, Takahiro Imaizumi, Atsushi Toyoda, Takeshi Ooyama
AIAA Journal Vol. 53 ( 9 ) page： 2781 - U23 2015.9
Frequency modulation in shock wave-boundary layer interaction by repetitive-pulse laser energy deposition Reviewed International journal
T. Tamba, H. S. Pham, T. Shoda, A. Iwakawa and A. Sasoh
Physics of Fluids Vol. 27 ( 9 ) page： 10.1063/1.4931924 2015.9
Low-Boom Performance Demonstration of a Long, Staged Aftbody Reviewed International journal
Toyoda Atsushi, Suzuki Kakuei, Imaizumi Takahiro, Sasoh Akihiro
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES Vol. 58 ( 5 ) page： 307 - 309 2015
Staged Aftbody for Alleviation of Tail Boom Reviewed International journal
Atsushi Toyoda , Kakuei Suzuki , Takahiro Imaizumi , Akihiro Sasoh
AIAA Journal Vol. 52 ( 12 ) page： 2899 - + 2014.12
Electrostatic Acceleration of Helicon Plasma using a Cusped Magnetic Field Reviewed International journal
S.Harada,T.Baba,A.Uchigashima,S.Yokota,A.Iwakawa,A.Sasoh,T.Yamazaki,and H.Shimizu
Applied Physics Letters Vol. 105 ( 19 ) page： 194101(4pages) 2014.11
Statistical behavior of post-shock overpressure past grid turbulence Reviewed International journal
Akihiro Sasoh,, Tatsuya Harasaki, Takuya Kitamura, Daisuke Takagi, Shigeyoshi Ito, Atsushi Matsuda, Kouji Nagata, Yasuhiko Sakai
Shock Waves - An International Journal on Shock Waves Vol. 24 ( 5 ) page： 489 - 500 2014.9
Laser Energy Deposition Effectiveness on Shock-Wave Boundary-Layer Interactions over Cylinder-Flare Combinations Reviewed International journal
T. Osuka, E. Erdem, N. Hasegawa, R. Majima, T. Tamba, S. Yokota, A. Sasoh, K. Kontis
Physics of Fluids Vol. 26 ( 9 ) page： 096103(17pages) 2014.9
Supersonic aerodynamic performance of truncated cones with repetitive laser-pulse energy depositions Reviewed International journal
A. Sasoh, J.-H. Kim, K. Yamashita, T. Sakai
Shock Waves - An International Journal on Shock Waves Vol. 24 ( 1 ) page： 59 - 67 2014.1
On Invariants in Grid Turbulence at Moderate Reynolds Numbers Reviewed International journal
Takuya Kitamura,Kouji Nagata,Yasuhiko Sakai,Akihiro Sasoh,Osamu Terashima,Hiroki Saito,Tatsuya Harasaki
Journal of Fluid Mechanics Vol. 738 page： 378 - 406 2014.1
Repetitive Pulse Performance of 1-μm Laser Ablation Propulsion onto Aluminum Reviewed International journal
Hisashi Tsuruta , Bin Wang , Zhogyuan Wang , Shigeru Yokota, and Akihiro Sasoh
Journal of Propulsion and Power Vol. 30 ( 6 ) page： 1485 - 1489 2014
Aerospace Application Reviewed International journal
Sasoh Akihiro
MICRO-NANO MECHATRONICS - NEW TRENDS IN MATERIAL, MEASUREMENT, CONTROL, MANUFACTURING AND THEIR APPLICATIONS IN BIOMEDICAL ENGINEERING page： 271 - 285 2013
DRAG REDUCTION PERFORMANCE DUE TO REPETITIVE LASER PULSES ON THE BLUNT BODY Reviewed International journal
Kim Jae-Hyung, Sasoh Akihiro
PROCEEDINGS OF THE ASME/JSME/KSME JOINT FLUIDS ENGINEERING CONFERENCE 2011, VOL 1, PTS A-D page： 3363 - 3368 2012
Laser Ablation Propulsion Performance of Surface-Modified Polyoxymethylene Reviewed International journal
Sasoh Akihiro, Ogita Naoya, Shikida Mitsuhiro, Sinko John E.
JOURNAL OF PROPULSION AND POWER Vol. 28 ( 4 ) page： 840 - 847 2012
Wave Drag Reduction with Acting Spike Induced by Laser-Pulse Energy Depositions Reviewed International journal
Kim Jae-Hyung, Matsuda Atsushi, Sakai Takeharu, Sasoh Akihiro
AIAA JOURNAL Vol. 49 ( 9 ) page： 2076 - 2078 2011.9
Interactions among baroclinically-generated vortex rings in building up an acting spike to a bow shock layer Reviewed International journal
Kim Jae-Hyung, Matsuda Atsushi, Sasoh Akihiro
PHYSICS OF FLUIDS Vol. 23 ( 2 ) 2011.2
Effects of Propellant Surface Morphology on Laser Ablative Propulsion Performance Reviewed International journal
Ogita Naoya, Shikida Mitsuhiro, Sasoh Akihiro
BEAMED ENERGY PROPULSION: SEVENTH INTERNATIONAL SYMPOSIUM Vol. 1402 2011
Review on Japanese-German-US Cooperation on Laser-Ablation Propulsion Reviewed International journal
Scharring Stefan, Sinko John E., Karg Stephanie, Eckel Hans-Albert, Roeser Hans-Peter, Sasoh Akihiro, Ogita Naoya, Umehara Noritsugu, Tsukiyama Yosuke
BEAMED ENERGY PROPULSION: SEVENTH INTERNATIONAL SYMPOSIUM Vol. 1402 2011
In-Tube Rocket Propulsion Using Repetitive Laser Pulses Reviewed International journal
Sasoh Akihiro
JOURNAL OF THERMAL SCIENCE Vol. 20 ( 3 ) page： 201 - 204 2011
Efficient Supersonic Drag Reduction using Repetitive Laser Pulses of up to 80 kHz Reviewed International journal
Sasoh Akihiro, Kim Jae-Hyung, Yamashita Kiyokazu, Sakai Takeharu, Matsuda Atsushi
BEAMED ENERGY PROPULSION: SEVENTH INTERNATIONAL SYMPOSIUM Vol. 1402 2011
Supersonic Drag Reduction with Repetitive Laser Pulses Through a Blunt Body Reviewed International journal
Sasoh Akihiro, Sekiya Yohei, Sakai Takeharu, Kim Jae-Hyung, Matsuda Atsushi
AIAA JOURNAL Vol. 48 ( 12 ) page： 2811 - 2817 2010.12
Modulations of a weak shock wave through a turbulent slit jet Reviewed International journal
Kim Jae-Hyung, Sasoh Akihiro, Matsuda Atsushi
SHOCK WAVES Vol. 20 ( 4 ) page： 339 - 345 2010.8
A Review of Laser Ablation Propulsion Reviewed International journal
Phipps Claude, Bohn Willy, Lippert Thomas, Sasoh Akihiro, Schall Wolfgang, Sinko John
INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 Vol. 1278 page： 710 - + 2010
Critical Fluences And Modeling Of CO2 Laser Ablation Of Polyoxymethylene From Vaporization To The Plasma Regime Reviewed International journal
Sinko John E., Phipps Claude R., Tsukiyama Yosuke, Ogita Naoya, Sasoh Akihiro, Umehara Noritsugu, Gregory Don A.
BEAMED ENERGY PROPULSION Vol. 1230 page： 395 - + 2010
CO2 Laser Ablation Propulsion Area Scaling With Polyoxymethylene Propellant Reviewed International journal
Sinko John E., Ichihashi Katsuhiro, Tsukiyama Yosuke, Ogita Naoya, Sakai Takeharu, Umehara Noritsugu, Sasoh Akihiro
BEAMED ENERGY PROPULSION Vol. 1230 page： 207 - + 2010
CO2 Laser Ablation Area Scaling And Redeposition On Flat Polyoxymethylene Targets Reviewed International journal
Sinko John E., Scharring Stefan, Tsukiyama Yosuke, Ichihashi Katsuhiro, Ogita Naoya, Sasoh Akihiro, Umehara Noritsugu, Eckel Hans-Albert, Roeser Hans-Peter
INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 Vol. 1278 page： 538 - + 2010
Laser Propulsion Standardization Issues Reviewed International journal
Scharring Stefan, Eckel Hans-Albert, Roeser Hans-Peter, Sinko John E., Sasoh Akihiro
INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 Vol. 1278 page： 780 - + 2010
Usage Of Polyacetal Powders As Laser Ablation Propulsion Propellants Reviewed International journal
Sasoh Akihiro, Ogita Naoya, Sinko John E.
BEAMED ENERGY PROPULSION Vol. 1230 page： 163 - + 2010
Update On CO2 Laser Ablation Of Polyoxymethylene At 101 kPa Reviewed International journal
Sinko John E., Scharring Stefan, Ogita Naoya, Sasoh Akihiro, Eckel Hans-Albert, Roeser Hans-Peter
INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 Vol. 1278 page： 548 - + 2010
Survey Of CO2 Laser Ablation Propulsion With Polyoxymethylene Propellant Reviewed International journal
Sinko John E., Sasoh Akihiro
BEAMED ENERGY PROPULSION Vol. 1230 page： 231 - + 2010
Review: Laser-Ablation Propulsion Reviewed International journal
Phipps Claude, Birkan Mitat, Bohn Willy, Eckel Hans-Albert, Horisawa Hideyuki, Lippert Thomas, Michaelis Max, Rezunkov Yuri, Sasoh Akihiro, Schall Wolfgang, Scharring Stefan, Sinko John
JOURNAL OF PROPULSION AND POWER Vol. 26 ( 4 ) page： 609 - 637 2010
Modeling CO2 Laser Ablative Impulse with Polymers Reviewed International journal
Sinko John E., Phipps Claude R., Sasoh Akihiro
INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 Vol. 1278 page： 699 - + 2010
Measurement Issues In Pulsed Laser Propulsion Reviewed International journal
Sinko John E., Scharring Stefan, Eckel Hans-Albert, Roeser Hans-Peter, Sasoh Akihiro
BEAMED ENERGY PROPULSION Vol. 1230 page： 125 - + 2010
Richtmyer-Meshkov instability in laser plasma-shock wave interaction Reviewed International journal
Sasoh A., Mori K., Ohtani T.
SHOCK WAVES, VOL 2, PROCEEDINGS page： 1199 - + 2009
Wall-Propelled, In-Tube Propulsion with Repetitive-Pulse Laser Ablation Reviewed International journal
Sasoh Akihiro, Suzuki Shingo, Matsuda Atsushi
JOURNAL OF PROPULSION AND POWER Vol. 25 ( 2 ) page： 540 - 542 2009
Interaction between laser-induced plasma and shock wave over a blunt body in a supersonic flow Reviewed International journal
Sakai T., Sekiya Y., Mori K., Sasoh A.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING Vol. 222 ( G5 ) page： 605 - 617 2008.8
Ablative impulse characteristics of polyacetal with repetitive CO2 laser pulses Reviewed International journal
Suzuki Koji, Sawada Keisuke, Takaya Ryota, Sasoh Akihiro
JOURNAL OF PROPULSION AND POWER Vol. 24 ( 4 ) page： 834 - 841 2008
Access to space without energy and propellant on board Reviewed International journal
Sasoh Akihiro, Jeung In-Seuck, Choi Jeong-Yeol
BEAMED ENERGY PROPULSION Vol. 997 page： 37 - + 2008
Diagnostics and impulse performance of laser-ablative propulsion Reviewed International journal
Sasoh Akihiro, Mori Koichi, Anju Kohei, Suzuki Koji, Shimono Masaya, Sawada Keisuke
BEAMED ENERGY PROPULSION Vol. 997 page： 232 - + 2008
Wall-ablative, laser-driven in-tube accelerator Reviewed International journal
Sasoh Akihiro, Suzukia Shingo, Matsuda Atsushi
HIGH-POWER LASER ABLATION VII, PTS 1-2 Vol. 7005 2008
Time-resolved measurements of impulse generation in pulsed laser-ablative propulsion Reviewed International journal
Anju Kohei, Sawada Keisuke, Sasoh Akihiro, Mori Koichi, Zaretsky Eugene
JOURNAL OF PROPULSION AND POWER Vol. 24 ( 2 ) page： 322 - 329 2008
Moderate-acceleration launch using repetitive-pulse laser ablation in a tube Reviewed International journal
Sasoh Akihiro, Suzuki Shingo, Shimono Masaya, Sawada Keisuke
JOURNAL OF PROPULSION AND POWER Vol. 24 ( 5 ) page： 1144 - 1146 2008
Spatio-temporal filament behaviour in a dielectric barrier discharge plasma actuator Reviewed International journal
Sasoh A., Kikuchi K., Sakai T.
JOURNAL OF PHYSICS D-APPLIED PHYSICS Vol. 40 ( 14 ) page： 4181 - 4184 2007.7
Expansion tube operation with thin secondary diaphragm Reviewed International journal
Furukawa Takeshi, Aochi Takanobu, Sasoh Akihiro
AIAA JOURNAL Vol. 45 ( 1 ) page： 214 - 217 2007.1
Pressure effect in a shock-wave-plasma interaction induced by a focused laser pulse Reviewed International journal
Sasoh A., Ohtani T., Mori K.
PHYSICAL REVIEW LETTERS Vol. 97 ( 20 ) 2006.11
Impactless, in-tube sabot separation technique useful for modest-sized supersonic ballistic ranges Reviewed International journal
Sasoh Akihiro, Oshiba Shin
REVIEW OF SCIENTIFIC INSTRUMENTS Vol. 77 ( 10 ) 2006.10
Shock-tube operation with laser-beam-induced diaphragm rupture Reviewed International journal
Sasoh A, Takahashi T, Watanabe K, Torikai H, Yang QS
AIAA JOURNAL Vol. 44 ( 5 ) page： 1110 - 1112 2006.5
Acceleration history in laser-ablative impulse measured using Velocity Interferometer (VISAR) Reviewed International journal
Mori Koichi, Anju Kohei, Sasoh Akihiro, Zaretsky Eugene
HIGH-POWER LASER ABLATION VI, PTS 1 AND 2 Vol. 6261 2006
Ambient pressure dependence of laser-induced impulse onto polyacetal Reviewed International journal
Watanabe Keiko, Mori Koichi, Sasoh Akihiro
JOURNAL OF PROPULSION AND POWER Vol. 22 ( 5 ) page： 1149 - 1151 2006
Speckle-beam oriented schlieren technique Reviewed
Yusuke NAKAMURA, Takumi SUZUKI, Kiyoshi KINEFUCHI, Akihiro SASOH
Experiments in Fluids Vol. 62 ( 13 ) 2021.1
Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests Reviewed
Kazuhiro MAEDA, Daisuke TSUBAKINO, Susumu HARA, Akihiro SASOH
Mechanical Engineering Journal Vol. 17 ( 5 ) page： 20 - 276 2020.10
In-tube shock wave compression by piston effect of unsteady jet Reviewed
Daisuke KUWABARA, Hirokatsu KAWASAKI, Akira IWAKAWA, Akihiro SASOH, Tetsuya YAMASHITA and Koji TAGUCHI
Mechanical Engineering Journal Vol. 17 ( 3 ) 2020.4
Application of laser energy deposition to improve performance for high speed intakes Reviewed
A. Russell, M. Myokan, H. Bottini, A. Sasoh, H. Zare-Behtasha and K. Kontis,
Propulsion and Power Research Vol. 19 ( 1 ) page： 15 - 25 2020.3
Similar Thrust Performance in Diverging-Magnetic-Field Electrostatic Thruster with Monoatomic Propellants Reviewed
Daisuke Ichihara, and Akihiro Sasoh
Journal of Propulsion and Power Vol. 35 ( 1 ) page： 236 - 238 2019.1
Effects of Repetitive Laser Energy Deposition on Supersonic Duct Flows
Hoang Son Pham, Manabu Myokan, Takahiro Tamba, Akira Iwakawa, and Akihiro Sasoh
AIAA JOURNAL Vol. 56 ( 2 ) page： 542-553 2018
Operation Characteristics of Applied-Field Magnetoplasmadynamics Thruster Using Hollow Cathode
Hayato KASUGA, Jeohun JEONG, Keisuke MIZUTANI, Akira IWAKAWA, Akihiro SASOH, Kohei KOJIMA, Tatsuya KIMURA, Yoshihiro KAWAMATA, and Masaaki YASUI
Transactions of The Japan Society for Aeronautical and Space Sciences Vol. 16 ( 1 ) page： 69-74 2018
Finite response time of shock wave modulation by turbulence
Inokuma Kento, Watanabe Tomoaki, Nagata Koji, Sasoh Akihiro, Sakai Yasuhiko
PHYSICS OF FLUIDS Vol. 29 ( 5 ) 2017.5
Effects of magnetic field profile near anode on ion acceleration characteristics of a diverging magnetic field electrostatic thruster
D. Ichihara, A. Iwakawa, and A. Sasoh
Journal of Applied Physics Vol. 122 ( 4 ) page： 043302(10pages) 2017
Power matching between plasma generation and electrostatic acceleration in helicon electrostatic thruster
Daisuke Ichihara, Yoshiya Nakagawa, Akira Uchigashima, Akira Iwakawa, Akihiro Sasoh, and Takuya Yamazaki
Acta Astronautica Vol. 139 page： 157–164 2017
Changes in divergence-free grid turbulence interacting with a weak spherical shock wave
T. Kitamura, K. Nagata, Y. Sakai, A. Sasoh, and Y. Ito
Physics of Fluids Vol. 29 page： 065114(9pages) 2017
Mach-number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over Blunt-Body
Akira Iwakawa; Tatsuro Shoda; Ryosuke Majima; Son Hoang Pham; Akihiro Sasoh
Transactions of the JSASS / Aerospace Technology Japan Vol. 60 ( 5 ) page： 303–311 2017
Impacts of laser energy deposition on flow instability over double-cone model
Hoang Son Pham, Tatsuro Shoda, Takahiro Tamba, Akira Iwakawa and Akihiro Sasoh
AIAA Journal Vol. 55 ( 9 ) page： 2992-3000 2017
Electrostatic/magnetic ion acceleration through a slowly diverging magnetic nozzle between a ring anode and an on-axis hollow cathode
Akihiro Sasoh, Keisuke Mizutani, and Akira Iwakawa
AIP Advances Vol. 7 page： 065204(6pages) 2017
Ablation Spot Area and Impulse Characteristics of Polymers Induced by Burst Irradiation of 1μm Laser Pulses
Hisashi Tsuruta, Oskar Dondelewski, Yusuke Katagiri, Bin Wang and Akihiro Sasoh
Acta Astronautica Vol. 136 page： 46-54 2017
Ten-Ampere-Level, Applied-Field-Dominant Operation in Magnetoplasmadynamic Thrusters
Daisuke Ichihara, Tomoki Uno, Hisashi Kataoka, Jaehun Jeong, Akira Iwakawa, and Akihiro Sasoh
Journal of Propulsion and Power Vol. 33 ( 2 ) page： 360-369 2017
Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body
Iwakawa Akira, Shoda Tatsuro, Majima Ryosuke, Pham Son Hoang, Sasoh Akihiro
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES Vol. 60 ( 5 ) page： 303-311 2017
Suppression of low-frequency shock oscillations over boundary layer by repetitive laser pulse energy deposition Reviewed
Akira Iwakawa,Tatsuro Shoda,Hoang Son Pham,Takahiro Tamba,Akihiro Sasoh
aerospace Vol. 3(2) page： 13 2016
Field experiment of blast wave pressure modulation past a turbulent flow Reviewed
Takahiro Tamba, Daiki Furukawa, Yuma Aoki, Masaya Kayumi, Akira Iwakawa, Akihiro Sasoh, Takehiro Matsunaga, Mitsuo Izumo, Yuta Sugiyama, Tomoharu Matsumura, and Yoshio Nakayama
Science and Technology of Energetic Materials Vol. 77 ( 4 ) page： 91-97 2016
Suppression of low-frequency shock oscillations over boundary layer by repetitive laser pulse energy deposition
Akira Iwakawa, Tatsuro Shoda, Hoang Son Pham, Takahiro Tamba, Akihiro Sasoh
Aerospace Vol. 13 ( 2 ) page： Article number 13 2016
Operation Characteristics of Steady-State, Applied Field, Rectangular Magnetoplasmadynamics (MPD) Thruster
D.Ichihara, S.Harada, H.Kataoka, S.Yokota, A.Sasoh
Journal of the Japan Society for Aeronautical and Space Sciences Vol. 63 ( 2 ) page： 37-44 2015
Influence of Microscopic Crater Formation on Impulse Generated with Repetitive Pulsed Laser Ablation
Hisashi Tsuruta, Bin Wang, Zhogyuan Wang, Akihiro Sasoh
Aerospace Technology Japan Vol. 13 page： 33-36 2015
Low-Boom Performance Demonstration of a Long, Staged Aftbody
Atsushi Toyoda , Kakuei Suzuki , Takahiro Imaizumi , Akihiro Sasoh
Trans.Japan Soc.Aero.Space Sci Vol. 58 ( 5 ) page： 307-309 2015
Ring-Force Balance System for Small Wind Tunnels Reviewed
Akira IWAKAWA,Takeshi OSUKA,Tatsuro SHODA,Akihiro SASOH,Hiromitsu KAWAZOE
Transactions of The Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan Vol. 13 page： 51-60 2015
Supersonic Drag Reduction over a Blunt-Body by Combination of Conical Spike and Energy Deposition
A. Iwakawa, T. Osuka, R. Majima, T. Sakai, A. Sasoh
Journal of the Japan Society for Aeronautical and Space Sciences Vol. 62 ( 3 ) page： 99-106 2014
Repetition Frequency Dependence of Wave Drag Reduction Induced by Laser-Pulse-Energy Depositions Reviewed
Akira IWAKAWA, Takeharu SAKAI, Akihiro SASOH
Aerospace Technology Japan Vol. 11 page： 53-60 2013
Operation Characteristics of a Steady-State, Two-Dimensional MPD Thruster Using a Hollow Cathode
Masaki Yonemoto, Akihiro Sasoh
28 ISTS Special Issue of Transaction of JSASS Vol. 10 page： Pb_7-Pb_12 2012
Laser Ablation Propulsion Performance of Surface-Modified Polyoxymethylene
Akihiro Sasoh, Naoya Ogita, Mitsuhiro Shikida, John E. Sinko
Journal of Propulsion and Power Vol. 28 ( 4 ) page： 840-847 2012
格子乱流のエネルギー減衰域における不変量について
北村拓也,長田孝二,佐宗章弘,酒井康彦,寺島修,齋藤大輝, 原崎 辰耶
日本機械学会論文集（B 編） Vol. 78 ( 795 ) page： 1928-1941 2012
Preheating Technique to Enhanse the Laser Ablation Impulse from Polymer Materials Reviewed
Koichi Mori , Akihiro Sasoh
International Journal of Aerospace Innovations Vol. 3 ( 1 ) page： 51-57 2011
Review of CO2 laser ablation propulsion with polyoxymethylene Reviewed
John E. Sinko and Akihiro Sasoh
International Journal of Aerospace Innovations Vol. 3 ( 2 ) page： 93-129 2011
Impact Fracture Behavior of Ceramics and PE-Fiber-Reinforced Mortars
Yasuhiro Tanabe, Masayoshi Yamada1, Akihiro Sasoh, Minoru Kunieda
Key Engineering Materials Vol. 484 page： 75-81 2011
胴体先端形状修正による翼胴型超音速複葉翼機のソニックブーム低減化
大久保正幸, 豊田篤，山下博, 小川俊広，大林茂，清水克也，鈴木角栄，松田淳，佐宗章弘
日本航空宇宙学会論文集 Vol. 59 ( 688 ) page： 119-125 2011
In-Tube Rocket Propulsion Using Repetitive Laser Pulses
Akihiro Sasoh
Journal of Thermal Science Vol. 20 ( 3 ) page： 1-4 2011
Interactions among baroclimically-generated vortex rings in building up an acting spike to a bow shock layer
Jae-Hyung Kim, Atsushi Matsuda, Akihiro Sasoh
PHYSICS OF FLUIDS 23 page： 021703-1-4 2011
Experimental Determination of the Impulse Coupling Coefficient - Standardization Issues Reviewed
S. Scharring, J. E. Sinko, A. Sasoh, H.-A. Eckel and H.-P. Roser
International Journal of Aerospace Innovations Vol. 3 ( 1 ) page： 33-43 2011
Wave Drag Reduction with Acting Spike Induced by Laser-Pulse Energy Depositions Reviewed
Jae-Hyung Kim, Atsushi Matsuda, Takeharu Sakai, Akihiro Sasoh
AIAA Journal Vol. 49 ( 9 ) page： 2706-2078 2011
Experimental-Numerical Combination Diagnostics for Near-Field Flow over Supersonic Flight Model
Atsushi Matsuda, Katsuya Shimizu, Kakuei Suzuki, Akihiro Sasoh, Keiichi Murakami, & Takashi Aoyama
Transactions of JSASS Space Technology of Japan Vol. 9 page： 37-41 2011
Aluminum-extrusion, square-bore, aero-ballistic range for launching three-dimensional projectiles
International Journal of Aerospace Innovations Vol. 2 ( 3 ) page： 147-156 2010.9
The modulations of weak shock wave through turbulent slit jet
Shock Waves ( 20 ) page： 339-345 2010
Supersonic Drag Reduction with Repetitive Laser Pulses through a Blunt Body
Akihiro Sasoh,Yohei Sekiya,Takeharu Sakai,Jae-Hyung Kim and Atsushi Matsuda
AIAA Journal Vol. 48 ( 12 ) page： 2811-2817 2010
Review: Laser Ablation Propulsion
C. Phipps, M. Birkan, W. Bohn, H.-A. Eckel, H. Horisawa, T. Lippert, M. Michaelis, Y. Rezunkov, A. Sasoh, W. Schall, S. Scharring, and J. Sinko
Journal of Propulsion and Power Vol. 126 ( 4 ) page： 609-637 2010
*Wall-Propelled, In-Tube Propulsion with Repetitive-Pulse Laser Ablation
Akihiro Sasoh, Shingo Suzuki and Atsushi Matsuda
Journal of Propulsion and Power Vol. 25 ( 2 ) page： 540-542 2009
Ablative Impulse Characteristics of Polyacetal with Repetitive CO2 Laser Pulses Reviewed
Koji Suzuki, Keisuke Sawada Ryota Takaya, Akihiro Sasoh
Journal of Propulsion and Power Vol. 24 ( 4 ) page： 834-841 2008.7
Time-Resolved Measurements of Impulse Generation in Pulsed Laser-Ablative Propulsion Reviewed
Kohei Anju, Keisuke Sawada, Akihiro Sasoh, Koichi Mori, Eugene Zaretsky,
Journal of Propulsion and Power Vol. 24 ( 2 ) page： 322-329 2008.3
Impulse Generation Mechanisms in Laser-Driven In-Tube Accelerator Reviewed
Choi, J.-Y., Sasoh, A., Jeung, I.-S., Urabe, N. and Kleine, H.
Transactions of The Japan Society for Aeronautical and Space Sciences Vol. 51 ( 172 ) page： 71-77 2008
Moderate-Acceleration Launch Using Repetitive-Pulse Laser Ablation In Tube Reviewed
Sasoh, A., Suzuki, S, Shimono, M. and Sawada, K.
Journal of Propulsion and Power Vol. 24 page： in press 2008
Interaction Between laser-Induced Plasma and Shock Wave Over a Blunt Body in a Supersonic Flow Reviewed
Takeharu Sakai, Yohei Sekiya, Koichi Mori, and Akihiro Sasoh
Journal of Aerospace Engineering Vol. 222 page： 605-617 2008
レーザパルスにより誘起されるプラズマ-衝撃波干渉場 Reviewed
森浩一，大谷俊朗，佐宗章弘
日本機械学会論文集B Vol. 73 ( 727 ) page： 670-675 2007.3
Expansion Tube Operation with Thin Secondary Diaphragm Reviewed
Takeshi Furukawa, Takanobu Aochi and Akihiro Sasoh
AIAA J. Vol. 45 ( 1 ) page： 214-217 2007.1
Spatio-temporal filament behavior in a dielectric barrier discharge plasma actuator Reviewed
A. Sasoh, K. Kikuchi, and T. Sakai
Journal of Physics D: Applied Physics Vol. 40 page： 4181-4184 2007
*Pressure effect in plasma-shock wave interaction induced by laser pulse irradiation over a parabola Reviewed
A. Sasoh, T. Ohtani and K. Mori
Physical Review Letters Vol. 97 ( 20 ) 2006.11
Ambient Pressure Dependence of Laser-Induced Impulse onto Polyacetal Reviewed
K. Watanabe, K. Mori and A. Sasoh
J. Propulsion and Power Vol. 22 ( 5 ) page： 1148-1151 2006.10
Impact-less, in-tube sabot separation useful for modest-sized supersonic ballistic ranges Reviewed
Akihiro Sasoh and Shin Oshiba
Review of Scientific Instruments Vol. 77 ( 10 ) 2006.10
Shock Tube Operation with Laser Beam Induced Diaphragm Rupture Reviewed
A. Sasoh, T. Takahashi, K. Watanabe, H. Torikai, and Q-S. Yang
AIAA Journal Vol. 44 ( 5 ) page： 1110-1112 2006.5
Multiband Radiation Model for Simulation of Galileo Probe Entry Flowfield Reviewed
S. MATUSYAMA, Y. SHIMOGONYA, N. OHNISHI, A. SASOH AND K. SAWADA
Journal of Thermophysics and Heat Transfer Vol. 20 ( 3 ) page： 611-614 2006.5
Suppression of discharge current oscillations in a Hall Thruster Reviewed
N. Yamamoto, S. Yokota, K. Watanabe, A. Sasoh, K. Komurasaki and Y. Arakawa
Trans. Japan Soc. Aero. Space Sci. Vol. 48 ( 161 ) page： 169-174 2005
Numerical Simulation of Galileo Probe Entry Flowfield with Radiation and Ablation Reviewed
S. Matsuyama, N. Ohnishi, A. Sasoh and K. Sawada,
Journal of Thermophysics and Heat Transfer Vol. 19 ( 1 ) page： 28-35 2005
Behavior of bubbles induced by the interaction of a laser pulse with a metal plate in water Reviewed
A. Sasoh, K. Watanabe, Y. Sano and N. Mukai
Applied Physics A Vol. 80 ( 7 ) page： 1497-1500 2005
Blast wave characteristics under laser-driven in-tube accelerator operation conditions, Reviewed
X. Yu, T. Ohtani, S. Kim, T. Ogawa, I-S. Jeung and A. Sasoh
Science and Technology of Energetic Materials Vol. 66 ( 2 ) page： 274-282 2005
Impulse Generation Using a 300-J-Class Laser with Confinement Geometries in Air Reviewed
K. Watanabe and A. Sasoh
Transaction of the Japan Society for Aeronautical and Space Sciences Vol. 48 ( 159 ) page： 49-52 2005
Impulse dependence on propellant condition in laser-driven in-tube accelerator Reviewed
A. Sasoh, N. Urabe, S. Kim and I.-S. Jeung
Transaction of the Japan Society for Aeronautical and Space Sciences Vol. 48 ( 160 ) page： 63-70 2005
レーザーピーニングで誘起される水中圧力波に対する金属板厚の影響 Reviewed
渡辺圭子, 佐野雄二, 向井成彦, 鳥飼宏之, 佐宗章弘
Vol. 5 ( 339 ) page： 161-166 2004
Distributed-Memory Parallelization of Radiative Transfer Calculation in Hypersonic Flow Reviewed
S. Matsuyama, N. Onishi, A. Sasoh and K. Sawada
Parallel Computational Fluid Dynamics-New Frontiers and Multi-Disciplinary Applocations page： 491-498 2003
Parallel Computation of Fully-Coupled Hypersonic Radiating Flowfield Using Multi-Band Model Reviewed
S. Matsuyama, T. Sakai, A. Sasoh and K. Sawada
Journal of Thermophysics and Heat Transfer Vol. 17 page： 21-28 2003
Laser-Powerd Launch in Tube Reviewed
A. Sasoh, M. Kister, N. Urabe and K. Takayama
Transactions of the Japan Society for Aeronautics and Space Sciences Vol. 46 ( 151 ) page： 52-54 2003
High Ram-Acceleration Using Open-Base Projectile Reviewed
Y. Hamate, A. Sasoh and K. Takayama
Journal of Propulsion and Power Vol. 19 page： 190-195 2003
Impulse scaling in laser-driven in-tube accelerator Reviewed
A. Sasoh, N. Urabe, S. Kim and I. -S. Jeung
Applied Physics A Vol. 77 page： 349-352 2003
Frequency Characteristics and Dynamical Behaviors of Self-Modulation In Vertical-Cavity Suface-Emitting Lasers Reviewed
Q. Yang and A. Sasoh
Optics Communications Vol. 219 page： 307-315 2003
Numerical Investigation of High-Enthalpy Flows Generated by Expansion Tube Reviewed
H. Otsu, T. Abe, Y. Ohnishi, A. Sasoh and K. Takayama
AIAA Journal Vol. 40 page： 2423-2430 2002
Impact of Unsteady Disturbance on Multi-Lane Traffic Flow Reviewed
A. Sasoh
Journal of the Physical Society of Japan Vol. 71 page： 989-996 2002
Shock Wave Relation Containing Lane Change Source Term for Two-Lane Traffic Flow Reviewed
A. Sasoh and T. Ohara
Journal of the Physical Society of Japan Vol. 71 page： 2075-2083 2002
Numerical and Experimental Investigation of Wave Dynamic Processes In High-Speed Train/Tunnels Reviewed
Z. Jiang, K. Matsuoka, A. Sasoh and K. Takayama
Acta Mechanica Sinica Vol. 18 page： 209-226 2002
Impulse Enhancement of Laser Propulsion In Tube Reviewed
A. Sasoh, J-Y. Choi, I-S. Jeung, N. Urabe, H. Kleine and K. Takayama
Postepy Astronautyki Vol. 27 page： 40-50 2001
Gun Interior Ballistic Performance with Ammonium Nitrate-Alcohol Propellants Reviewed
A. Sasoh, T. Ogawa, K. Takayama, K. Ikuta, N. Nagayasu and S. Ohtsubo
Journal of Propulsion and Power Vol. 17 page： 120-124 2001
*Laser-driven in-tube accelerator Reviewed
A. Sasoh
Review of Scientific Instruments Vol. 72 page： 1893-1898 2001
Plural voltage minima in an arc-heated channel flow Reviewed
A. Sasoh
Physics of Plasmas Vol. 8 page： 1376-1383 2001
Small-Bore Ram Accelerator Operation Reviewed
A. Sasoh, Y. Hamate and K. Takayama
Journal of Propulsion and Power Vol. 17 page： 622-628 2001
Effective Test Time Evaluation in High-Enthalpy Expansion Tube Reviewed
A. Sasoh, Y. Ohnishi, D. Ramjaun, K. Takayama, H. Otsu and T. Abe
AIAA Journal Vol. 39 page： 2141-2147 2001
Nonlinear Stability of Optimal Velocity Traffic Flow Model to Unsteady Disturbance Reviewed
A. Sasoh
Journal of the Physical Society of Japan Vol. 70 page： 3161-3166 2001
Ionizing Nitrogen and Air Flows in a Superorbital Expansion Tube Reviewed
T. J. McIntyre, A. I. Bishop, A. M. Thomas, A. Sasoh and H. Rubinsztein-Dunlop
AIAA Journal Vol. 38 page： 1685-1691 2000
Quantitative Effects of Projectile-Launch Tube Wall Friction on Ballistic Range Operation Reviewed
A. Sasoh, S. Ohba and K. Takayama
AIAA Journal Vol. 38 page： 1709-1715 2000
Flow Establishment over Constrictor in Arcjet Operation Reviewed
A. Sasoh
Transactions of the Japan Society for Aeronautical and Space Sciences Vol. 43 page： 23-30 2000
プリル硝安－アルコール混合物(ANA)の爆薬特性 Reviewed
永易伸生, 河野雄次, 大坪信武, 生田一成, 佐宗章弘, 高山和喜
火薬学会誌 Vol. 61 page： 114-119 2000
Projectile acceleration in a single-stage gun at breech pressures below 50 MPa Reviewed
A. Sasoh, S. Ohba and K. Takayama
Shock Waves Vol. 10 page： 235-240 2000
High-Enthalpy Expansion Tube Experiments with Gas Injection Reviewed
A. Sasoh, R. G. Morgan, B. N. Littleton, T. J. McIntyre and A. I. Bishop
AIAA Journal Vol. 38 page： 2253-2259 2000
Ram accelerator operations at acceleration level up to 6 × 104 g Reviewed
Y. Hamate, A. Sasoh and K. Takayama
Journal de Physique IV Vol. 10 ( Pr11 ) page： 3-9 2000
Laser-propelled ram accelerator Reviewed
A. Sasoh
Journal de Physique IV Vol. 10 ( Pr11 ) page： 41-47 2000
Investigation on utilization of liquid propellant in ballistic range experiments Reviewed
A. Sasoh, S. Ohba, and K. Takayama
Vol. 60 page： 205-211 1999
Diaphragm rupture. Impingement by a conically-nosed, ram-accelerator projectile Reviewed
A. Sasoh, J. Maemura, S. Hirakata, K. Takayama, J. Falcovitz
Shock Waves Vol. 9 page： 19-30 1999
Use of ammonium nitrate-alcohol (ANA) for ballistic range propellant Reviewed
A. Sasoh, T. Ogawa, K. Takayama
Shock Waves Vol. 9 page： 291-294 1999
Experiments on Attenuation of Weak Shock Waves in High-Speed Train Tunnels Reviewed
A. Sasoh, K. Matsuoka, K. Takayama, S. Hirano, S. Ono, Y. Makino and K. Ootsuta
JSME International Journal, Series B Vol. 41 page： 814-821 1998
衝撃波管実験に有用な任意同期マルチプレクサシステムの開発 Reviewed
佐宗 章弘, 川端荘平, 門脇忠
日本航空宇宙学会誌 Vol. 46 page： 311-313 1998
Technology and Application Aspects of Applied Field Magnetoplasmadynamic Propulsion Invited Reviewed
G. Krulle, M. Auweter-Kurtz and A. Sasoh
Journal of Propulsion and Power Vol. 14 page： 754- 763 1998
Numerical and Theoretical Studies on Detonation Initiation by A Supersonic Projectile Reviewed
Y. Ju, G. Masuya and A. Sasoh
Proceedings of 27th Symposium (International) on Combustion page： 2225-2231 1998
Application of sound-absorbent plastic to weak-shock-wave attenuators Reviewed
K. Ootsuta, K. Matsuoka, A. Sasoh and K. Takayama
Review of Scientific Instruments Vol. 69 page： 1724-1729 1998
高速列車トンネル突入による圧縮波の衝撃波への遷移 Reviewed
佐宗章弘, 松岡敬, 高山和喜
日本機械学会論文集(B編) Vol. 63 page： 3944-3951 1998
ラム加速機の始動過程に関する実験研究 Reviewed
佐宗章弘, 平形修二, 高山和喜
日本航空宇宙学会誌 Vol. 46 page： 37-45 1998
Attenuation of weak shock waves along pseudo-perforated walls Reviewed
A. Sasoh, K. Matsuoka, K. Nakashio, E. Timofeev, K. Takayama, P. Voinovich, T. Saito, S. Hirano, S. Ono. Y. Makino
Shock Waves Vol. 8 page： 149-159 1998
Ram Accelerator Operation Analysis in Thermally Choked and Transdetonative Propulsive Modes Reviewed
A. Sasoh and C. Knowlen
Transactions of the Japan Society for Aeronautical and Space, Sciences Vol. 40 page： 130-148 1997
Numerical Study of Detonation Initiation by a Supersonic Sphere Reviewed
Y. JU and A. Sasoh
Transactions of the Japan Society for Aeronautical and Space, Sciences Vol. 40 page： 19-29 1997
Hollow Projectile Operation in the Ram Accelerator Reviewed
A. Sasoh, A. J. Higgins, C. Knowlen, A. P. Bruckner
Journal of Propulsion and Power Vol. 12 page： 1183-1186 1996
The reflection of a shock wave over a cone Reviewed
J. Yang, A. Sasoh, K. Takayama
Shock Waves Vol. 6 page： 267-273 1996
Thrust Formula for Applied-Field Maganetoplasmadynamic Thrusters Derived from Energy Conservation Equation Reviewed
A. Sasoh and Y. Arakawa
Journal of Propulsion and Power Vol. 11 page： 351-356 1995
Experimental investigation on tunnel sonic boom Reviewed
K. Takayama, A. Sasoh, O. Onodera, R. Kaneko, Y. Matsui
Shock Waves Vol. 5 page： 127-138 1995
*Characterization of disturbance propagation in weak shock-wave reflections Reviewed
A. Sasoh and K. Takayama
Journal of Fluid Mechanics Vol. 277 page： 331-345 1994
Simple formulation of magnetoplasmadynamic acceleration Reviewed
A. Sasoh
Physics of Plasmas Vol. 1 page： 464-469 1994
Generalized Hall Acceleration Reviewed
A. Sasoh
Journal of Propulsion and Power Vol. 10 page： 251-254 1994
Scaled train tunnel simulator for weak shock wave generation experiment Reviewed
A. Sasoh, O. Onodera and K. Takayama
Review of Scientific Instruments, Vol. 65 page： 3000-3004 1994
A high-resolution thrust stand for ground tests of low-thrust space propulsion devices Reviewed
A. Sasoh and Y. Arakawa
Review of Scientific Instruments Vol. 64 page： 719-723 1993
Numerical Study on Atom-Molecule Radiation Flowfield around a Hypersonic Blunt Body Reviewed
X.-Y. Chang, A. Sasoh and T. Fujiwara
Transactions of the Japan Society for Aeronautics and Space Sciences Vol. 35 page： 177-186 1993
バリスティック・レンジによる極超音速流実験（第１報）画像観測及びその処理方法 Reviewed
張 新宇, 辺見 真, 佐宗 章弘, 藤原 俊隆
日本航空宇宙学会誌 Vol. 41 page： 81-87 1993
*Electromagnetic Effects in an Applied-Field Magnetoplasmadynamic Thruster Reviewed
A. Sasoh and Y. Arakawa
Journal of Propulsion and Power Vol. 8 page： 98-102 1992
A weak shock wave reflection over wedges Reviewed
A. Sasoh, K. Takayama and T. Saito
Shock Waves Vol. 2 page： 277-281 1992
再突入時に形成される極超音速非平衡衝撃波層からの輻射熱伝達
佐宗章弘, 張新宇, 村山俊之, 藤原俊隆
日本航空宇宙学会誌 Vol. 39 page： 531-538 1991
荒川義博外部磁場のあるＭＰＤ推進機におけるホール加速 Reviewed
佐宗章弘, アンダース E. ソレム
日本航空宇宙学会誌 Vol. 37 page： 528-534 1989
Steady-State Permanent Magnet Magnetoplasmadynamic Thruster Reviewed
Y.Arakawa and A.Sasoh
Journal of Propulsion and Power Vol. 5 page： 301-304 1989
Steady-State MPD Arc Thruster with a Permanent Magnet Reviewed
Y.Arakawa and A.Sasoh
Journal of Propulsion and Power Vol. 4 page： 287-289 1988
Compressible Fluid Dynamics and Shock Waves
Akihiro Sasoh（ Role： Sole author）
Springer 2020 （ ISBN:978-981-15-0503-4 ）
圧縮性流体力学・衝撃波
佐宗章弘（ Role： Sole author）
コロナ社 2017.3
ながれの事典
神部勉（編）（ Role： Joint author）
丸善 2004
電気推進ロケット入門
栗木恭一,荒川義博（編）（ Role： Joint author）
東京大学出版会 2003
Ram Accelerators
K. Takayama and A. Sasoh (eds)（ Role： Joint author）
Springer-Verlag, Heidelberg 1998
衝撃波ハンドブック
高山 和喜(編)（ Role： Joint author）
シュプリンガー・フェアラーク東京 1995
Square-bore ballistic range for launching three-dimensional projectiles International conference
Supersonic Drag Reduction with Repetitive Laser Pulses through a Blunt Body International conference
40thAIAA Plasmadynamics and Laser Conference
Supersonic Drag Reduction with Repetitive Laser Pulses through a Blunt Body International conference
47th AIAA Aerospace Sciences Meeting
Plasma Behavior Induced by Repetitive Laser Pulses
39th Plasmadynamics and Lasers Conference, Seattle, Washington
Wall-Propelled, In-Tube Propulsion with Repetitive-Pulse Laser Ablation
39th Plasmadynamics and Lasers Conference, Seattle, Washington
Unsteady Interaction of Blunt Bodies With Laser Induced Plasma in a Supersonic Flow
39th Plasmadynamics and Lasers Conference, Seattle, Washington
Wall-ablative, laser-driven in-tube accelerator
High-Power Laser Ablation Ⅶ, Taos, NM, USA
Moderate-Acceleration Launch Using Repetitive-Pulse Laser Ablation In Tube
46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Computational Simulation of Local Impulse Generation in Intense Laser-Solid Interaction
46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Optical Observation of Discharge Plasma Structure in DBD Plasma Actuator
38th AIAA Plasmadynamics and Lasers ConferenceIn conjunction with the16th International Conference on MHD Energy Conversion , Miami, FL
Time-resolved and Integrated Laser Ablative Impulse Performance of Polyacetal
38th AIAA Plasmadynamics and Lasers ConferenceIn conjunction with the16th International Conference on MHD Energy Conversion , Miami, FL
Laser-Ablative Propulsion Using Polyacetal at Low Ambient Pressures
45th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Impulse Generation by Nd:YAG Laser Ablation of Aluminum
45th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Experiments of Laser^Pulse-Induced Drag Modulation in Supersonic Flow International conference
37th Plasmadynamics and Lasers Conference
Experiments of Laser-Pulse-Induced Drag Modulation in Supersonic Flow
37th AIAA Plasmadynamics and Lasers Conference, San Francisco, California
Acceleration history in laser-ablative impulse measured using Velocity Interferometer (VISAR) International conference
High-Power Laser Ablation Ⅵ, Taos, NM, U.S.A.
Expansion Tube Operation with Thin Secondary Diaphragm International conference
44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, U.S.A.
Expansion Tube Operation with Thin Secondary Diaphragm
44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Toward the Optimal Operation of Laser-Driven In-Tube Accelerator
44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Numerical Analysis of Expanding Nonequilibrium Plasma in a Gas-Driven Laser Propulsion
44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Time-Resolved Force Measurement over Laser-Ablated Materials
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Pulsed Laser Propulsion Performance of 11-cm Parabolic `Bell'Engines: CO2 TEA vs. EDL
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Physical Processes of the Interaction Between Laser-Generated Plasma and Blast Wave Appearing in Laser-Driven In-Tube Accelerator Configuration
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Impulse Characteristics of Laser-driven In-Tube Accelerator(LITA)
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-tube Accelerator Operation
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Numerical Simulation of Laser-Driven In-Tube Accelerator Operation
Fourth International Symposium on Beamed Energy Propulsion, Nara, Japan
Secondary diaphragm rupture processes in expansiontube
Proceedings of the 25th International Symposium on Shock Waves, Bangalore,India
Experimental study of the interaction between thelaser-generated plasma and a shock wave
Proceedings of the 25th International Symposium on Shock Waves, Bangalore,India
Propulsive impulse generation using laser pulse - solid/gas interactions International conference
International Workshop on Explosion, Shock Wave and Hypervelocity Phenomena 2005 (ESHP Workshop 2005)
Impulse Generation Scaling Laws in Laser-Driven In-Tube Accelerator
36th AIAA Plasmadynamics and Lasers Conference, Toronto, Ontario
Time-Resolved Measurement of the Impulse Generation Processes in POM Laser-Ablation
36th AIAA Plasmadynamics and Lasers Conference, Toronto, Ontario
Numerical Analysis of Laser-Driven In-Tube Accelerator Operation
43rd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Calculation of Unsteady Flowfield in Expansion Tube Using Contact Surface Resolving Technique
43rd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Fascinating Experimental Observations of Spatiotemporally Localized Flows Utilizing Pulsed Laser Energy International conference
Colloquium at Dept. Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute
Large impulse launch using 300-J CO2 TEA laser
Third International Symposium on Beamed Energy Propulsion, Troy, New York
Experimental Investigation of Airbreathing Laser Propulsion Engines: CO2TEA vs. EDL
Third International Symposium on Beamed Energy Propulsion, Troy, New York
Detailed Impulse Generation Mechanisms in the Laser-Driven In-Tube Accelerator
Third International Symposium on Beamed Energy Propulsion, Troy, New York
Presence of shock wave like structures in pedestrian motion
Proceedings of the 24th International Symposium on Shock Waves, Beijing, China
Active diaphragm rupture with laser beam irradiation
Proceedings of the 24th International Symposium on Shock Waves, Beijing, China
Impulse characteristics of laser-induced blast wave in monoatomic gases
Proceedings of the 24th International Symposium on Shock Waves, Beijing, China
Shock wave phenomena in underwater laser peening
Proceedings of the 24th International Symposium on Shock Waves, Beijing, China
A Pulsed Plasma Thruster Using Water as the Propellant
40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Fort Lauderdale, Florida
Laser impulse generation required for space debris deorbiting(Invited Paper)
High-Power Laser Ablation Ⅴ,Taos, New Mexico, USA
Laser-Induced Shock Impulse Generation and Its Aerospace Applications
42nd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Laser Impulse Generation in Flight
42nd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Active Shock-tube-diaphragm Rupture with Laser Beam Irradiation
42nd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada
Useful In-space Impulse Generation Powered by Laser Energy
Second International Symposium on Beamed Energy Propulsion, Sendai, Japan
In-Tube Laser Propulsion; Performance and Application Prospects
Second International Symposium on Beamed Energy Propulsion, Sendai, Japan
Dependence of Initial Plasma Size on Laser-driven In-Tube Accelerator (LITA) Performance
Second International Symposium on Beamed Energy Propulsion, Sendai, Japan
Trajectory-Based Heating Analysis of Galileo Probe Entry Flowfield with Radiation and Ablation
36th AIAA Thermophysics Conference, Orlando, Florida
Advanced Laser-driven In-Tube Accelerators
34th AIAA Plasmadynamics and Lasers Conference, Orlando, Florida
High-power/applied-field MPD research activities in Japan -- Past and future prospects International conference
Technology and System Options Towards Megawatt Level Electric Propulsion, Gli Incontri di Lerici, Anno II-International Workshop
レーザーとプラズマの相互作用による飛翔体の加速
第15回「電磁力関連のダイナミックス」シンポジウム
有限時間エネルギー開放を伴う流動とインパルス発生
火薬学会 第62回通常総会並びに2003年度春季研究発表講演会
In-Tube Laser Propulsion Configurations
First International Symposium on Beamed Energy Propulsion, Huntsville, Alabama
Vertical Launch Performance of Laser-driven In-Tube Accelerator
First International Symposium on Beamed Energy Propulsion, Huntsville, Alabama
Numerical Analysis of Carbon Dioxide Flowfield in Expansion-Tube
8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, St. Louis, Missouri
Assessment of the Thermochemical Model for a Super-orbital Reentry Flow
8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, St. Louis, Missouri
Numerical Simulation of Galileo Probe Entry Flowfield with Radiation
8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, St. Louis, Missouri
Laser-Driven In-Tube Accelerator Operation Using Monoatomic Gases
33rd Plasmadynamics and Lasers Conference, Maui, Hawaii
Numerical Study of Laser-Induced Pulsed Airbreathing Propulsion
33rd Plasmadynamics and Lasers Conference, Maui, Hawaii
Impulse enhancement by in-tude operation in laser propulsion (Invited Paper)
High-Power Laser Ablation Ⅳ,Taos,USA
Numerical study of non-ideal diaphragm rupture in expansion tube
AIAA Aerospace Sciences Meeting and Exhibit, 40th, Reno, NV
Open-base projectile performance in ram accelerator
AIAA Aerospace Sciences Meeting and Exhibit, 40th, Reno, NV
Pressure and Thrust Generation Using Laser Beam Focusing Through Forward-Facing Reflector
Proceedings of the 23rd International Symposium on Shock Waves, Fort Worth, Texas, USA
In-Situ Sampling of Gases and Debris from Volcanic Plumes
Proceedings of the 23rd International Symposium on Shock Waves, Fort Worth, Texas, USA
Shock Wave Phenomena in Multilane Traffic Flows
Proceedings of the 23rd International Symposium on Shock Waves, Fort Worth, Texas, USA
Magnetoplasmadynamic Experiments Using Expansion Tube
Proceedings of the 23rd International Symposium on Shock Waves, Fort Worth, Texas, USA
LITA (Laser-driven In-Tube Accelerator) operation under elevated pressures
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt Lake City, UT
Numerical and experimental studies of laser-driven ram accelerator
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt Lake City, UT
Numerical simulation of transient flowfield in expansion-tube
AIAA Thermophysics Conference, 35th, Anaheim, CA
Hypersonic flow generation and diagnostics in expansion tube
AIAA/NAL-NASDA-ISAS International Space Planes and Hypersonic Systems and Technologies Conference, 10th, Kyoto, Japan
Laser-Driven In-Tube Accelerator: Reusable Space Launch System International conference
Parallel computation of fully-coupled hypersonic radiating flowfield using multi-band model
Aerospace Sciences Meeting and Exhibit, 39th, Reno, NV
In-tube laser propulsion
AIAA Plasmadynamics and Lasers Conference, 31st, Denver, CO
RAMAC25 multi-stage operation
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 36th, Huntsville, AL
Ram Accelerator Research Activities at Shock Wave Research Center International conference
Fourth International Workshop on Ram Accelerators
Simulation of ablative mixing layers in superorbital flows
Proceedings of the 22nd International Symposium on Shock Waves
High acceleration operation in a small-bore ram accelerator
Proceedings of the 22nd International Symposium on Shock Waves
Soft launch using single-stage chemical gun
Proceedings of the 22nd International Symposium on Shock Waves
High acceleration ram accelerator operation
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 35th, Los Angeles, CA
Ballistic range performance of ammonium nitrate-alcohol (ANA) propellant
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 35th, Los Angeles, CA
Significance of unsteadiness in operation of the small bore ram accelerator
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 34th, Cleveland, OH
Ionization measurements in a super-orbital expansion tube
Advanced Measurement and Ground Testing Technology Conference, 20th, Albuquerque, NM,
Experimental studies of 25-mm-bore ram accelerator at the Shock Wave Research Center
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 33rd, Seattle, WA
Benchmark test of reflection of weak shock waves from shallow wedges
Proceedings of the 21st International symposium on Shock Waves
Attenuation of weak shock waves along pseudo-perforated walls
Proceedings of the 21st International symposium on Shock Waves
Fluid dynamic processes of diaphragm rupturing by a conically-nosed projectile
Proceedings of the 21st International symposium on Shock Waves
Real-scale experimental simulation of tunnel sonic booms
Proceedings of the 21st International symposium on Shock Waves
Operation tests of a 25-mm-bore ram accelerator
ASME, SAE, and ASEE, Joint Propulsion Conference and Exhibit, 32nd, Lake Buena Vista, FL
Effect of finite rate chemical reactions on ram accelerator thrust characteristics
ASME, SAE, and ASEE, Joint Propulsion Conference and Exhibit, 31st, San Diego, CA
Equilibrium and nonequilibrium radiation heat transfer over a reentry blunt body
SAE, ASME, and ASEE, Joint Propulsion Conference, 26th, Orlando, FL
Steady-state permanent magnet MPD thruster
DGLR, and JSASS, International Electric Propulsion Conference,19th, Colorado Springs, CO
Shock Wave Moderation by Fore-Flow Nudge: Proof of Principle and Applications
Grant number：21H04589 2021.4 - 2025.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Authorship：Principal investigator
Grant amount：\42380000 （ Direct Cost: \32600000 、 Indirect Cost：\9780000 ）
Grant number：18H03813 2018.4 - 2021.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Sasoh Akihiro
Authorship：Principal investigator
Grant amount：\44460000 （ Direct Cost: \34200000 、 Indirect Cost：\10260000 ）
Interaction experiments were conducted in which the condition of the interacting states were independently changed using the originally developed "Counter-Driver Shock Tube". As a result of conducting the interaction experiments in which the shock wave Mach number, the turbulent flow Mach number, and the interaction distance were independently changed, it was shown that the interaction distance had a great influence on the deformation of the shock wave front, and the conventional concept of dealing with a steady state was found insufficient to describe the observed phenomena. From the experimental results, we were able to show the importance of introducing non-stationarity. It was shown that when the shock wave Mach number was relatively low and the turbulent Mach number was high, the shock wave front disappeared in the Schlieren image when the interaction distance was about 10 times or more of the integral scale. This fact was well explained by a model based on the Riemann problem.
Conceptual Study of a Space Debris Deorbit Mission
Grant number：16H02426 2016.4 - 2019.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Ebisuzaki Toshikazu, TAKIZAWA Yoshiyuki, SAKAKI Naoto
Authorship：Coinvestigator(s)
Space debris, in particular, cm-sized debris are important issue of space development. We performed a conceptual study for the deorbit mission by laser ablation with a high-intensity space-laser system. Among the steps of the deorbit operation of space debris, we performed the experiment of step 1; detection and step 2; tracking in the laboratory with 1/10 scale model of EUSO telescope. In addition, the optimization study revealed that the deorbit mission can work optimal condition in the sun-synchronous orbit, which can always stay in the twilight with the altitude of 600-900 km. Furthermore, we examined the ablation response for various debris materials and the way of the suppression of the rotation of them.
Modulation and active control of supersonic flow by introducing artificial disturbance
Grant number：15H02321 2015.4 - 2018.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Sasoh Akihiro
Authorship：Principal investigator
Grant amount：\44720000 （ Direct Cost: \34400000 、 Indirect Cost：\10320000 ）
In this study, we aimed in understanding mechanisms of supersonic flow modulation by artificial disturbances, and in developing their applications to supersonic flight. A counter-driver shock tube with a 120 mm * 120 mm square-cross-section was developed so that experiments of shock wave-turbulence interaction became possible. As a result, it was experimentally demonstrated that the longer the propagation distance the more the shock wave surface became disturbed, thereby leading to the topological transition of the wave front. Moreover, by introducing repetitive laser energy pulses on to Mach 1.9 flow, the shock wave oscillation experienced frequency modulation to a low frequency regime so that total pressure loss was reduced in a supersonic duct.
Demonstration of thrust performance of helicon plasma electrostatic thruster
Grant number：15K14250 2015.4 - 2016.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\3900000 （ Direct Cost: \3000000 、 Indirect Cost：\900000 ）
This study aimed in investigating the ion beam energy characteristics and ion beam current characteristics to optimize operation condition in helicon electrostatic thruster (HEST), which was an originally-developed, high-power, large-payload space propulsion thruster. With a low propellant flow rate, a ring anode whose inner diameter equaled that of the helicon plasma source exit yielded the best performance. In this case, the inner surface of the anode acted a primary role in the electrostatic acceleration. When the anode inner diameter bacome larger, the contribution of its side surface became larger; the electrostatic acceleration performance was much degraded when the side surface was covered with an insulator.
Turbulence modulation simulation of sonic boom using field explosion experiments
Grant number：26630442 2014.4 - 2015.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
SASOH Akihiro, YOKOTA Shigeru, SAKAI Yasuhiko, NAGATA Kouji, NAKAYAMA Yoshio
Authorship：Principal investigator
Grant amount：\3900000 （ Direct Cost: \3000000 、 Indirect Cost：\900000 ）
In this study, experimental simulation method of evaluating overpressure variation induced by a blast wave interacting with turbulent flow was developed. The blast wave was generated using a 0.51-gram power. The turbulent flow was generated with an electrical fan, duct and grid. Overpressure histories were measured using four microphones set symmetrically. A 40 % standard deviation in overpressure was obtained, thereby demonstrating spatiotemporal behavior as the result of the shock wave-turbulence interaction.
Grant number：25220914 2013.5 - 2018.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
ISHIKAWA Takashi, YOSHIMIZU Daisuke
Authorship：Coinvestigator(s)
An in-situ forming technique of carbon fiber reinforced thermoplastic (CFRTP) composites is studied, in which impregnation and lamination processes are operated simultaneously in a single manufacturing process. For this purpose, a manufacturing device which consists mainly of a diode laser and a compaction roller is developed. The results show that the bending modulus and strength of CFRTP fabricated by the present manufacturing device are as high as the ones obtained by a conventional hot press machine. A three-dimensional visualization method with high-speed stereo cameras is developed to analyze the deformation dynamics of CFRTP during the impact fracture. The obtained results suggest that the interfacial adhesion between carbon fiber (CF) and resin, and the property of resin strongly affect the impact fracture processes. Based on this observation, a new surface treatment for CF improving the impact strength is proposed for future application.
Grant number：25249123 2013.4 - 2018.3
科学研究費助成事業 基盤研究(A)
石川 隆司, 佐宗 章弘, 池田 忠繁, 田邊 靖博, 酒井 武治
Authorship：Coinvestigator(s)
(1)直接その場成形法の実現可能性評価及び(2)CFRTPの成形プロセスの解明に関しては、実験に使う繊維、樹脂の選定を始めた。特に、開繊糸とナイロンシートから なるセミプレグの観察および含浸時間評価、ホットプレスによるCFRTP成形 実験を行い、レーザーを用いたその場製造技術確立に資する試料データを取得した。また、真空バック樹脂含浸法でナイロン6のCFRTPを作製したところ、弾性率は予想値の8～9割であったが、強度は半分程度であり、含浸は上手くいっているが、繊維とナイロンと の密着が不足していると推察された。このため、サイジング剤及び表面処理剤の探索を開始した。
(3)CFRPの破壊プロセスの解明に関しては、高速衝突試験装置の整備の 準備を始めた。
25年度が最終年度であるため、記入しない。
25年度が最終年度であるため、記入しない。
Development of actively-controlled counter driver shock tube capable of precise flow control
Grant number：25630390 2013.4 - 2014.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\3900000 （ Direct Cost: \3000000 、 Indirect Cost：\900000 ）
We have developed a shock tube with two counter drivers the condition to each of which can be set independently. From three criteria, (1) the effective diaphragm rupture time and associated shock wave formation distance, (2) pressure loss and flow uniformity, and (3) temporal jitter in the diaphragm rupture control were adopted to evaluate the driver performance. As the result, the device using an pneumatic cylinder was employed, thereby demonstration experiments including those for shock wave-turbulence interaction were conducted.
Grant number：24656519 2012
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）
A new Mach-Zehnder interferometer, in which two interferograms with different wavelengths are imaged onto a single plate, has been developed. As light sources, semi-conductor lasers with the respective wavelengths of 473 nm and 593 nm are used. A dual-band-path filter is used to eliminate the effect of emission from ionized gas.The two-dimensional density distributions of heavy particles and electrons are obtained through digital data processing. Demonstration measurement was conducted with laser-pulse-generated plasma in a chamber of 350 mm in diameter and 400 mm in length, thereby obtaining a heavy particle density of 5×1025m-3and a degree of ionization of 10 % in the axi-symmetric field.
Demonstration of tractor beam laser propulsion using aerodynamics effects
Grant number：23656537 2011
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）
'Tractor beam' thrust is defined in laser ablation propulsion as generating a thrust in the direction toward a laser device. In order to demonstrate the feasibility of this technique, a torsion-type impulse stand with a high accuracy was designed and manufactured. Using this, the generation of a tractor beam thrust was demonstrated both in the atmosphere and in vacuum.
Fly By Light Power: Improvement in High-Speed Aerodynamics with Low-Power Deposition
Grant number：22226014 2010.4 - 2015.3
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
SASOH Akihiro, SAKAI Yasuhiko, SAKAI Takeharu, MATSUDA Atsushi, YOKOTA Shigeru, NAGATA Kouji
Authorship：Principal investigator
Grant amount：\223730000 （ Direct Cost: \172100000 、 Indirect Cost：\51630000 ）
This study aimed for vastly improving supersonic aerodynamic performance by repetitive laser pulse energy depositions. The following results were obtained: (1) Utilizing the momentum production from the interaction between a shock wave and a laser-heated bubble, a wave drag reduction of higher than 20 % and an efficiency of energy deposition of 10 (1000%) were obtained. (2) It was demonstrated that boundary layer separation could be suppressed by the laser energy deposition onto shock wave-boundary interaction region. (3) A standard deviation of one order in magnitude larger than the average decrement in post-shock overpressure modulation past turbulence was obtained, thereby demonstrating the possibility of strongly influencing pressure fields even through weak spatiotemporal inputs.
Search material components for developing high anti-impact behavior and easy machining
Grant number：22560682 2010 - 2012
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
TANABE Yasuhiro, UMEHAR Noritsugu, SASOH Akihiro
Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid)
In this study, we conducted impact tests and investigated the effects of projectile materials on impact phenomena of CFRP by using three-dimensional (3D) measurement under high-velocity projectile impact. The following two were mainly revealed: the first is that
(1) the ballistic limit range was affected by the kinetic energy of the projectile and this kinetic energy was proportional to the diameter of the projectile. When projectile was deformed, its deformation energy was not negligible small. The second is that
(2) the main mechanism of energy absorption in CFRPs is their deformation. CFRPs, consisting of high-strength carbon fiber having large-failure-strain and deformable resin, could absorb large kinetic energy of a projectile. We can find a large trend that highly energy dissipated resins tended to show lower thrust-forces. Both of high resistivity against impact and easy-machining can be compatible in a CFRP.
Grant number：21656221 2009 - 2010
科学研究費助成事業 挑戦的萌芽研究
佐宗 章弘
Authorship：Principal investigator
Grant amount：\3200000 （ Direct Cost: \3200000 ）
本研究では,マッハ数2の超音速流れ中に置かれたトランケーティドコーン(円錐台,以下T-cone)の先端にレーザーパルスによるエネルギーを繰返し付与し,抗力低減と節約推進パワーが付与パワー量を上回る条件が両立する作動を実証し,今後の民間超音速飛行の実現に向けて一つの好材料を提供することを目標としている。平成21年度の実験は,JAXA宇宙科学研究本部(以下ISAS/JAXA)の超音速風洞を使用したが,天秤の分解能が本研究の目的のためには不測していることが判明し,抗力軽減特性データを取得できなかった。そこで,今年度は名古屋大学の吸込み風洞を用いて実験した。平成21年度末に繰返し周波数100kHzのパルスレーザーが導入されたので,それを活用して高繰返し効果によるバーチャルスパイク形成の実証と抗力軽減特性を取得した。高繰返しレーザーパルスを,風洞のBK7窓を通して試験部に導入し,モデルの内部を通さず直接モデル前方に集光させた。モデル形状(面積比,頂角)を固定し,レーザーパルスエネルギーと繰返し周波数を制御変数として,レーザーパワー付与したときの抗力測定実験を行った。その結果,レーザーパルスが誘起する高温・低密度領域と物体前方に形成される衝撃波との干渉によって生成される渦輪の作用によって,物体前方に低圧領域が滞留し,この渦輪の滞留時間を長くすることが,時間平均抗力低減に鍵を握ることがわかった。これは,トランケーティドコーンの先頭台部の面積を大きくするほど効果的であるが,反面ベースラインの抗力が低減した。先頭に台部を有しない形状,すなわち円錐では,レーザーパルスによる抗力低減量は小さく,パワー利得は1をはるかに下回る結果となった。さらに,台部を平面ではなく適切な曲率の凹面とすることによって,渦輪の滞留時間が増加し,抗力低減性能が向上することを実証した。
Basic Study of Push-Pull Hybrid Propulsion
Grant number：19206089 2007 - 2009
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
SASOH Akihiro, SAKAI Takeharu, MATSUDA Atsushi, MORI Koichi
Authorship：Principal investigator
Grant amount：\41210000 （ Direct Cost: \31700000 、 Indirect Cost：\9510000 ）
This study aimed in the establishment of 'push-pull hybrid propulsion,' in which a small fraction of propulsion power is supplied to reduce a wave drag over a body in supersonic flow. We obtained an efficiency of energy deposition of up to 10. The drag reduction mechanisms, in which vortex rings generated by shock wavelaser-heated gas interaction played an important role were clarified.
Fundamental Research for Silent Supersonic Transport Based on Supersonic Biplane Theory
Grant number：19206086 2007 - 2009
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
OBAYASHI Shigeru, ASAI Keisuke, NAGAI Hiroki, SASOU Akihiro, KAWAZOE Hiromitsu, MATSUNO Takashi, NAKAHASHI Kazuhiro, MATSUSHIMA Kisa, JEONG Shinkyu, TSUBOI Nobuyuki, NAKAMURA Yoshiaki, MIYAJI Kouji, SATO Tetsuya, MATSUO Akiko, SAWAI Syujiro, FUJITA Kazuhisa, KOBAYASHI Hiroaki, TAGUCHI Hideyuki
Authorship：Coinvestigator(s)
Supersonic Biplane Theory is a concept of eliminating wave drag and sonic boom by using shock wave interaction between two airfoils facing each other. The following research topics are investigated in this research to construct and validate the theory : Definition of three-dimensional wing configuration and its optimization, Investigation of low speed characteristics of supersonic biplane by using CFD and EFD, Supersonic wind tunnel test of starting process of three-dimensional supersonic biplane, Free flight experiment of supersonic biplane using ballistic range.
Transdisciplinary Research for Silent Supersonic Aircraft by Integrating Computation and Experiment
Grant number：15206091 2003 - 2006
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
OBAYASHI Shigeru, HAYASE Toshiyuki, SASOH Akihiro, SAITOH Tsutomu, NAKAHASHI Kazuhiro, MATSUSHIMA Kisa
Authorship：Coinvestigator(s)
One of the fundamental problems preventing commercial transport aircraft from supersonic flight is the generation of strong sonic booms. The strength of the shock waves generated by an aircraft flying at supersonic speed is a direct function of both the aircraft's weight and its occupying volume; it has been very difficult to sufficiently reduce the shock waves generated by the heavier and larger conventional supersonic transport (SST) configuration to meet acceptable at-ground sonic-boom levels.
Our team first re-analyzed the classic Busemann biplane configurations to understand its basic wave cancellation concept using modern Computational Fluid Dynamics (CFD) tools. We then designed a two-dimensional (2-D) supersonic biplane that not only shows the desired aerodynamic characteristics at its design condition, but also outperforms a zero-thickness flat-plate airfoil. (Zero-thickness plat-plate airfoils are known as the most efficient monoplane airfoil at supersonic speeds.) Also we studied biplane performance not only at their design Mach numbers but also at off-design conditions. We extended the analysis to 3-D wing configurations as well.
In parallel to the computational studies, we carried out series of experiments. The first experiment conducted here was the sonic boom experiment using gas gun. The N-wave was captured successfully. The second experiment was the 2 D wind tunnel test using Indraft Wind Tunnel Facility newly constructed in this research. In addition, conventional wind tunnel tests were conducted using existing wind tunnels. These experiments revealed important off-design flow features to be further studies by using CFD.
The main research result is the development of the supersonic biplane theory. Biplane configuration allows canceling shock waves created by supersonic objects. It can be unconventional and innovative concept for future supersonic transport.
Grant number：14080203 2002 - 2006
科学研究費助成事業 特定領域研究
谷口 宏充, 今村 文彦, 佐宗 章弘, 後藤 章夫, 山田 功夫, 斎藤 務, 大島 弘光
Authorship：Coinvestigator(s)
火山探査移動観測ステーション:当初に掲げた‘2km離れた地点からの無線操縦と観測データの送受信'は実現していることが確認されているので、本年度は、実際の噴火観測への運用を確実にするため、1986年の大島三原山の噴火推移に即してシナリオを作成し観測演習を行った。登坂走行や観測上の問題点などを明らかにしつつ、演習としてはおおむね満足すべき成果を得、実用への目処をつけた。火山観測用ドップラーレーダ:今年度はシステムを構成するデータ取得、処理系のプログラムの修正と改良を実施した。実際の火山噴火を対象とした試験観測をおこなうことは出来なかったが、野外における実験観測を通して実用化への目途をつけた。ヘリコプター投下型GPS観測システム:2005年10月浅間山において取得したデータに予期しないデータの欠落があり、これが測位解析結果の良くない原因であることが分かった。そこでデータの欠落があり、短く切れているデータを捨てたうえで再度解析を行ったところ、かなり改善された。火山爆発模擬実験装置:クレータ形成について、高圧ガスの駆動力と砂の挙動の力学的マッチングによってその飛散形態が大きく異なる観測結果をモデル化した。高圧ガス容器内の圧力履歴は一次元準定常ガス放出モデルで再現できること、砂の運動とガスの放出がマッチングするとドーム状の飛散形態となり、運動量交換が最大になることなどがわかった。火山性爆風数値計算コード:爆発的噴火による爆風の発生と伝播、そして火砕サージの流下過程を模擬する計算コードを開発してきた。昨年度で実際の地形をも考慮した、火砕サージの3次元数値模擬計算コード開発を行い、本年度は有珠火山と桜島火山などの火山を対象に数値実験を繰り返し、現象の再現は成功している。火山性津波数値計算コード:喜界カルデラ津波に対し、崩壊モデルや火砕流突入モデルなどを検討し、津波規模の推定解析を行った。
Grant number：14208046 2002 - 2004
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
INUTAKE Masaaki, ANDO Akira, HATTORI Kunihiko, SASOH Akihiko, YOSHINUMA Mikirou
Authorship：Coinvestigator(s)
This research aims to clarify an electromagnetic acceleration mechanism of plasma flow and to control Mach number of the plasma flow using a magnetic nozzle for optimization of the plasma acceleration. Especially, we have directly observed the electromagnetic force (Lorentz force) accelerating the plasma in the Laval-type magnetic nozzle and compared it with the flow velocity measurement. We investigated in detail the formation of the Lorentz force in various magnetic field configurations and effects on the acceleration. The results are summarized as follows.
1.The thermal energy of the ion was converted into the flow energy by passing through the Laval type magnetic nozzle at the muzzle of Magneto-Plasma-Dynamic arcjet (MPDA). The ion Mach number of the plasma attains to more than unity and the supersonic plasma flow was obtained.
2.Spatial profiles of the several plasma parameters, flow velocity, ion temperature and Mach number of the plasma, were consistent with the theoretical results derived from the one-dimensional isentropic flow model.
3.It was experimentally clarified that the magnetic field in the plasma flow became weak caused by the diamagnetic effect and the converging magnetic field was spontaneously formed near the MPDA. The Lorenz force by the azimuthal current and the inward magnetic field decelerated ions in the plasma.
4.Adding a strong diverging magnetic field improved the deformation of the magnetic field and changes the deceleration force to acceleration force, which resulted in a large increase of plasma flow velocity.
As a result, we have shown that the electromagnetic force acting on the plasma flow could be controlled directly by shaping the external magnetic field, and clarified the plasma acceleration mechanism and its control methods.
Study of physics and practical applications of laser-driven in-tube accelerator
Grant number：13852014 2001 - 2005
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
SASOH Akihiro, TANIUCHI Tetsuo, KOBAYASHI Hideaki, SAWADA Keisuke, YAMAGUCHI Shigeru, HORISAWA Hideyuki
Authorship：Principal investigator
Grant amount：\124280000 （ Direct Cost: \95600000 、 Indirect Cost：\28680000 ）
Basic and application studies were conducted on the laser-driven, in-tube accelerator which had been developed by the head investigator. The operation principle was experimentally validated in 4-m-high vertical launch experiment. The impulse generation mechanisms were experimentally and numerically studied by highlighting the interactions among shock waves, expansion waves and laser-generated plasma and accompanying fluid-dynamics instabilities. A scaling law of its propulsion performance was established. The impulse enhancement using laser ablation was experimentally demonstrated. Those are useful for practical applications. In this device, the momentum coupling coefficient, which is defined as the ratio of an impulse to a laser energy, can be tripled owing to a confinement effect and with appropriate setting of the working gas species and its fill pressure. The momentum coupling coefficient scales with the reciprocal of the speed of sound, which was experimentally validated using three kinds of monoatomic gases, argon, krypton and xenon. The secondary effect of their ionization potential on the impulse was also obtained. The impulse performance is uniquely characterized using a dimensionless momentum coupling coefficient, the dimensional momentum coupling coefficient multiplied by the speed of sound, and a dimensionless parameter, the ratio of the fill pressure multiplied by an effective projectile volume to the laser energy. From the experimental and numerical analysis, it is concluded that the impulse performance can be optimized from the effective expansion volume of the laser plasma. In the laser-ablative performance experiment, polyacetal exhibited the best performance ; its impulse is sensitive to the ambient pressure. At an appropriate laser fluence, the impulse becomes highest at ambient pressures below 100 Pa. This favorable performance can be useful not only for improving the propulsive performance of the device but also for other various space applications including space debris deorbiting.
Grant number：12CE2003 2000 - 2004
科学研究費助成事業 特別推進研究(COE)
井小萩 利明, 高山 和喜, 林 一夫, 佐宗 章弘, 齊藤 務, 小原 拓, 谷口 宏充, 井小萩 利明, 樋口 博
Authorship：Coinvestigator(s)
特別推進研究「複雑媒体中の衝撃波現象の解明とその学際応用」では、(1)複雑組成の媒体中の衝撃波現象、(2)化学変化、相変化を伴う媒体中の衝撃波現象、(3)複雑境界を過ぎる衝撃波、また、極低温および高温境界を過ぎる衝撃波、および(4)きわめて大きな時間変動を伴う衝撃波現象を解明し、その成果を医療、地球物理など学際領域研究に発展させ、また、産業応用への展開の基盤技術の確立を目指した。また、この本研究拠点が国内外に衝撃波学際応用研究センターとなることを目標に研究を推進した。ここに、過去および最近5年間の衝撃波研究の成果が体系化され、本拠点活動が国内の衝撃波研究会活動を支援するばかりでなく、平成17年3月に国際衝撃波学会(International Shock Wave Institute)の設立に結びついたこと述べ、特別推進研究「衝撃波」を総括する。主な研究成果は:
i)基礎的研究くさびを過ぎる衝撃波反射に粘性効果に起因する遷移遅れを実験と精緻な数値模擬結果との対比から、始めて実証した。この現象が凹面および凸面さらに円錐面にも現れることを明らかにし、流体力学の教科書を書き直すに足る事実を見いだしている。また、大型縦型衝撃波管内に加速度計を内蔵した球を吊し衝撃波を負荷するという巧妙な実験で、衝撃波負荷での球の非定常抗力を実測し、衝撃波ないし爆風負荷での各種形状物体の非定常抗力計測に始めて成功している。この結果は数値模擬法との組み合わせで、粉塵気体中の衝撃波伝播に非定常抗力の効果明らかにしている。縦型無隔膜衝撃波管、大型無隔膜衝撃波管などを設計法を開発して、衝撃波の実験研究の精度を飛躍的に向上させ、また、衝撃波研究に微小爆薬の爆発を導入するなど、独創的な衝撃波実験法を発展させている。高性能の二段式軽ガス銃を設備し、弾道飛行実験装置の機能を加えて、高速飛行および高速衝突の動力学の体系化に成功している。直径1mのシュリーレン鏡を導入して大視野で、高レイノルズ数流れの二重露光ホログラフィー干渉計測定法を確立し、さらに、これを位相変位ホログラフィー干渉計法を展開し、音波に近い非常に弱い衝撃波の計測に成功している。気体、液体、混相媒体中の衝撃波現象の解明に適した数値模擬法を開発している。
ii)水中衝撃波現象の解明とその医療応用 医学部の共同者と衝撃波の医療応用を推進し、衝撃波医療システムが構築されようとしている。水中でパルスレーザー光照射でのマイクロ衝撃波発生の物理を解明し、成果を種々の医療装置開発に結びつけることに成功している。カテーテル内でのレーザー光照射で気泡と衝撃波を発生し、カテーテル先端から直径0.1mm、速度20m/s程度の水ジェットを制御して噴出させ、これを空気中で用いて生体軟組織の切開装置を試作し、また、これを血管内で用いて低侵襲的な脳血栓血行再建術装置を試作している。これら装置での基礎実験、動物実験を終了させて現在臨床実験を開始しようとしている。また、衝撃波と細胞の相互作用を組織学的にまた生化学的に解明するための、医学と工学の連携研究が進行中である。パルスレーザー光を金属膜に作用させ発生するレーザーアブレージョンでの金属膜の高速変形を用いて微粒子を高速で打ち出す過程を詳細に解明して独創性の高いドラッグデリベリー法を開発している。この原理は微粒子分布と貫通深さを制御した物理的遺伝子導入法の開発に拡張され、現在、実用研究が進行中である。
iii)地球物理、火山学への応用地球物理学者との連携で研究を推進し、地球進化史に巨大隕石衝突が重要な役割を果たし、そのとき固体および水中衝撃波が激変の素過程となっていることを、アナログ実験と数値模擬により様々の角度から実証している。また、火山の爆発的な噴火では短時間のエネルギー解放が重要な素過程となり、同様に衝撃波の関与が重要となっていることを実証している。特に、マグマの微粒化の動力学的機序をアナログ実験で解明した。
iv)産業応用爆発騒音、自動車排気騒音およびトンネルソニックブームの機序を解明し、防止あるいは低減法を提案している。また、レーザー光を用いる新しい海底岩盤掘削法開発の基礎を確立した。
v)学会活動5年間の拠点形成過程を通じて日本衝撃波研究会事務局を、また、Shock Wave International Journalの編集長と編集事務を担当し、さらに、拠点活動の一環として平成13年アジア太平洋衝撃波研究会を発足させ、これを平成17年3月国際衝撃波学会(International Shock Wave Institute)の設置に発展させている。
Shock Dynamic Study of Laser Ablation Induced Drug Delivery
Grant number：12355009 2000 - 2002
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
TAKAYAMA Kazuyoshi, SAITO Tsutomu, SASOH Akihiro, IKOHAGI Toshiaki, TAKAHASHI Akira, WADA Hiroshi
Authorship：Coinvestigator(s)
In the Interdisciplinary Shock Wave Research Center, Tohoku University, we have aimed to apply the shock wave phenomena to medicine. We have already finished the extracorporeal shock wave lithotripsy and now are working for the development of system for revascularization of cerebral thrombosis, which is expected to be completed in very near future. In these topics a shock wave plays always an important role*. When a Q-switched laser beam focused a spot on a metal foil surface, instantaneously a plasma cloud ejected from the spot and as its reaction a shock wave is generated inside the metal foil which propagate and reflected from the other surface. The plasma formation is called laser ablation. The reflected wave an expansion one and as a result of it the foil is instantaneously bulged at 2 to 5 km/s. When small* particles are attached on the metal surface these would be ejected at such a high speed at the moment laser beam irradiation. This principle has been applied to accelerate dry drug particles or metal particles* of the order of magnitude of one micron or so into human tissue. We have used Q-switched Nd:YAG laser focused on the surface of a 5 mm thick glass plate backed up with 0.1 mm this aluminum foil on which tungsten or gold particles were attached. We measured the particle ejection speed to be in the order of magnitude of 1 to 2 km/s. Injecting these particles against agarose cell, mouse liver, and mouse skin, we measured penetration depths against these and found the maximum penetration depth was about 6 mm for individual materials. The free flight of such small particles belongs to hypersonic Stokes flow which has never be discussed seriously in the field gas dynamics. We have developed numerical scheme to estimate particle free flight as well as penetration into soft tissues. We have examined with this method the penetration into cell lines in liquid solution and observed a beautiful penetration of a one micron tungsten particle into a cell. Based on these basic studies we concluded that this method is superior to the existing mechanical gene delivery systems and so robust and compact that it can be redesigned as a therapeutic device. We believe we have accomplished our main goal which we proposed at first.
Grant number：12555271 2000 - 2002
科学研究費助成事業 基盤研究(B)
佐宗 章弘, 生田 一成, 齋藤 努, 高山 和喜, 永易 伸生
Authorship：Principal investigator
Grant amount：\1700000 （ Direct Cost: \1700000 ）
本年度の計画として、昨年度試作した低リコイル高速射出装置の推進性能実験の実績を基に、その作動条件の最適化をさらに進める予定であったが、平成13年7月31日付けで基盤研究(S)の内定によりこの課題を辞退することとなった。これまでの研究成果で、低リコイルの初段射出装置として、火薬と軽ガスを組み合わせたハイブリット方式にすることが有効であることがわかった。これは、軽ガスを火薬で駆動することによって、初期の充填圧力を低く保ったまま一時的な高圧状態を作り出すことができ、さらに駆動気体となるヘリウムの比熱比が高く原子量が小さいため、高い音速をもつことによって、駆動気体としての好ましい性質を有するためであることがわかった。また、二段目の加速部としてはラム加速が有効であり、これはこれまでラム加速機の研究実績により、実験データベースがかなり整えられている。今年度は、これらを組み合わせて二段作動システムを稼動させる予定でいたが、上記の理由によりそこまでには至らなかった。しかし、初段加速、ラム加速に関する研究成果は、アメリカ航空宇宙学会のJournal of Propulsion and Powerや2002年1月に開催された同学会年会で発表し、国際的にも高い評価を受けた。特に、初段加速部における隔膜破断圧の設定法や飛行体自体の、軽量化については独自のアイディアを実証している。このうち、飛行体の軽量化については、open-base方式を開発し、周囲が高圧であっても飛行体の強度を損ねることなく、高速まで加速が可能であることを実証している。なお、本研究で培った低リコイル高速射出技術は、新しく採択された基盤研究(S)において、超音速条件でのレーザー加速の実証実験の初段打ち出し装置へ応用される見通しとなっている。
Basic research of the generation mechanism of aerodynamic noise
Grant number：12450073 2000 - 2002
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
INOUE Osamu, MOCHIZUKI Osamu, ISHII Katsuya, NAKAMURA Yoshiaki, HATAKEYAMA Nozomu, FUKUNISHI Yu
Authorship：Coinvestigator(s)
In this project, the generation and propagation mechanisms of aerodynamic noises generated by the motions of vortices and shock waves are investigated. We developed a highly-accurate finite difference numerical scheme (6-th order accurate in space and 4-th order in time) to solve the unsteady compressible Navier-Stokes equations. By applying the scheme to shock-vortex interaction problems, we found that noises are generated in response to the generation of reflected shock waves caused by the interaction, and that the generated reflected shock waves interact with vortices again and produce noises successively. This is an important finding on the mechanism of sound generation in supersonic turbulent flows. Next, we applied the scheme to the problems of aeolian tones generated by an obstacle in a uniform flow. The results showed that the generation frequency of the sound is equal to the fluctuation frequency of lift force and also to the shedding frequency of Karman vortices. We also found that the propagation of sound is affected by the Doppler effect and the propagation angle is determined by the Mach number. We also compared our numerical results with the prediction by Curle's acoustic analogy and pointed out that the Curle's analogy in its original form is incomplete and proposed an improved method which gives a close approximation to the correct solutions. We also proposed a new method which is effective to control actively the generation and propagation of aeolian tones generated by a circular cylinder in a uniform flow.
Grant number：12450391 2000 - 2002
科学研究費助成事業 基盤研究(B)
佐宗 章弘, 高山 和喜
Authorship：Principal investigator
Grant amount：\7800000 （ Direct Cost: \7800000 ）
本年度の計画として、昨年までのレーザー駆動管内加速装置の試作、インパルス、圧力測定実験の基礎データ取得の実験を基に、垂直打上実験とその詳細な推進性能データを取得する予定であったが、平成13年7月31日付けで基盤研究(S)の内定によりこの課題を辞退することとなった。
しかし、それまでの研究成果で本装置の作動が実際に可能であったことを実証することができ、さらに数値シュミレーションのための基礎データを取得することで、数値シュミレーションによる加速機構のより詳細なプロセスを明らかにすることができた。特に、管内に封入する作動気体の化学種や充墳圧力を変えることによって推進性能を制御できる点、管内での閉じ込め効果による性能向上、出口側からレーザー光を入射させる3点は、本研究のとくにアピールできる点であり、研究成果を外国の学会で発表し、本装置のオリジナリティーと実際に得られた推進性能について高い評価を得ている。この基礎研究は、将来の宇宙輸送システムに抜本的な改革をもたらす可能性を持っている。現在のロケットシステムは、ロケット本体に推進剤、酸化剤を搭載するため、特に打上げ時には、上空で使用する燃料/酸化剤を加速するために推力を出さねばならないというジレンマがある。これに対して、本研究のシステムは、作動気体は予め管内に封入しておくため、打ち上げコストを大幅に(1/10〜1/100)に削減できる可能性がある。また、飛行体の姿勢制御不要、レーザーに追尾機能搭載不要、レーザー光による周辺への危険性がなく、大気汚染、騒音の問題もない。近い将来、太陽光発電衛星からのレーザー光を利用した直接打上システム、軌道上での運動量発生システム、宇宙エレベータなどての実用展開の可能性も期待できる。これら基礎研究成果は、上記基礎研究(S)の研究課題に引き継がれ、実用展開を視野に入れたより高度な基礎研究に活用される見通しである。
Grant number：11875216 1999 - 2000
科学研究費助成事業 萌芽的研究
佐宗 章弘
Authorship：Principal investigator
Grant amount：\1700000 （ Direct Cost: \1700000 ）
これまで、大気圏再突入に関わる流体の研究は、壁面の電気的な条件が考慮されずになされてきたものが殆どだった。ところが、超軌道速度での再突入では電離度が10%を越えることも有り得るため、プラズマ流体としての取扱いが必要になる。本研究では、その中の代表的な現象である、固体壁の電気境界条件について実験研究を行った。まず、イクスパンション管を用いた超軌道速度流れの発生法を確立した。実験室の限られた環境でそのような極限的な高エンタルピー流れを発生させるため、自由ピストン駆動部の条件をチューンドオペレーション法を改良することによって確立した。また、試験気流の状態を、従来の静圧、ピトー圧測定のみに頼らず、衝撃波層の高速度写真撮影、時間分解発光分光測定を通して、より精度よく測定した。特に、上記分光測定によって加速気体と試験気体の接触面を明確に測定し、許容誤差の関数として試験時間を評価した。淀み点エンタルピーは、最高37MJ/kgまで達成した。試験気流中に静電探針を置いてその浮遊電位を測定したところ、境界層の状態に依存して大きく変動することがわかった。また、二波長ホログラフィー干渉計法による円柱周りの衝撃波層の可視化実験を行い、浮遊電位金属壁、グランド電位金属壁、絶縁物壁による電子密度の違いを測定した。しかし、その差異は測定誤差の範囲内であり、電子境界条件がシース外部の流れ場に大きな影響をもたらす条件は見出せなかった。本研究の結論として、固体壁の電気境界条件は流れ場の大きな構造を変えるまでには至らないが、浮遊電位は大きく変動し、再突入物体の通信、計測機器への配慮が必要となることが示唆された。
Study of real gas effects by using a Mach 20 hypersonic shock tube
Grant number：10044119 1998 - 1999
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B).
TAKAYAMA Kazuyoshi, SASOH Akihiro
Authorship：Coinvestigator(s)
In simulating experimentally atmospheric re-entry of space vehicles, shock wave technology is best used to create high temperature conditions which are otherwise impossible to generate by any together methods. The high temperature so far appearing during the atmospheric re-entry exceed 10,000 K so that air molecules will dissociate and then ionized. This process is name real gas effect. The present study aims to experimentally verify the hypersonic real gas effect by using a 100 mm x 180 mm hypervelocity shock tube that has been transported from the Institute of Aerospace Studies, University of Toronto in 1994. The present study is to refurbish this shock tube by adopting a detonation driver system in which the reflection of detonation waves in stoichiometric oxyhydrogm mixture is used and to quantitatively visualize hypersonic shock waves using double exposure holography interferometry.
The result obtained are summarized as following :
(1) A diaphragmless operation system has been adopted successfully in this shock tube. Its characteristics have been throughly investigated. Its higher degree of repeatability that has not been achieved among existing shock tubes has been confirmed.
(2) To ensure the initiation of detonations in the high pressure chamber, the transition from deflagration driven shock waves to detonation waves has been visualized using double exposure holographic interferometry. The effect of small particles shattering from the surface of micro-charges which initiate the chemical reaction.
(3) Finite fringe holographic interferometry has been applied to the experiments in (2). Finite fringe interferograms were quantitatively analyzed by using Fourier fringe analysis. Its measuring system has been established.
(4) Results obtained during two years of research works have been presented at international symposia. International collaboration with the Institute of Aerospace Studies, University of Toronto has been conducted.
Study on dynamic mechanism of perforation on cancer cells at shock waves exposures
Grant number：10450071 1998 - 1999
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
TAKAYAMA Kazuyoshi, HAYASHI Satoru, IORITANI Naomasa, SASHO Akihiro
Authorship：Coinvestigator(s)
Extracoporeal shock wave lithotripsy (ESWL), non-invasive removal of kidney stones, is one of the most peaceful applications of shock waves. As a collaboration project with Medical School of Tohoku University we have developed prototype lithotriptor which was approved by the Ministry of Health and Welfare. As a result of basic research, tissue damages during ESWL treatments have been clarified and we found a technology to damage living tissue in a controlled fashion. This technology is extended to cancer research with the combination of chemotherapy during which it was discovered punctuation on the cancer cells when shock waves were exposed on them. The mechanism of punctuation is found to be related with shock wave interaction with nonhomogeneity of a medium with local curvature. The goal of present research is to clarify the mechanism of the punctuation in details.
Results obtained are summarized as following :
(1) Optical flow visualization of shock/tissue interaction has been developed. However, it has a limitiation in its spatial resolution. In order to compensate it, we seek for model tissues which have analogous characteristics to living tissues, with which various analogue experiments have been conducted and the results have been numerically simulated.
(2) Finite fringe holographic interferometry has been developed and Fourier fringe analysis was well established. This method allowed to identify a slight density change created by shock wave exposures and was found to be effectively extended further shock/tissue interaction studies.
(3) Numerical methods have been developed to be compared with experiments. Interactions between shock waves and various gas liquid interfaces have been successfully simulated.
(4) A vertcal gas gun has been designed and constructed with which micro-shock/tissue interaction will be investigated. This is a facility which can directly simulate shock induced perforation on model tissue surface.
Development of measuring systems of dissociated oxygen in hypersonic tunnel flows
Grant number：09355034 1997 - 1999
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
TAKAYAMA Kazuyoshi, SUN Mingyu, SAITO Tsutomu, SASOH Akihiro
Authorship：Coinvestigator(s)
Hypersonic wind tunnel flows can provide data base which would support entire Japanese space projects including HOPE-X and forth coming named space shuttle projects. In particular, to resolve heat shielding of re-entry space vehicles, the existing shock tube has to be upgraded to satisfy the generation of these extreme conditions.
The aim of the present study is to develop the facility and measuring systems. Results obtained are summarized as following :
(1) The high pressure chamber of a 100 mm x 180 mm shock tube has been modified to detonation driving operation systems and a quickly opening valve has been adopted to ensure higher degree of repeatability. Its characteristics are numerically and experimentally clarified.
(2) The initiation of detonation waves was experimentally examined. A micro-charge ranging from 1.0 to 10 mg in weight was laser ignited in a detonation chamber, in order to clarify the transition from deflagration driven shock waves to detonation, in oxyhydrogen miters at initial pressure from 10 to 100 kPa. By using holographic interferometric observations, the boundary of initiations has been determined.
(3)Starting processes in two-dimensional and axisymmetric nozzles have been numerically and experimentally investigated. In the case of an axisymmetric nozzle, an aspheric lens shaped converging and diverging nozzle was constructed and collimated object beam could pass without creating any distortion of images of test section, with which a quantitative image data acquisition became possible.
(4) For the interpretation of experimental results, a dinette difference scheme using unstructured grids has been developed and a higher resolution has been obtained.
"Advanced Application of Gas-dynamic to Planetary Exploration"
Grant number：08305036 1996 - 1998
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
ABE Takashi, FUJIWARA Toshitaka, TAKAYAMA Kazuyoshi, NISHIDA Michio, SUZUKI Kojiro, HINATA M
Authorship：Coinvestigator(s)
The extensive research was made on application of gas-dynamics on the future planetary exploration, mainly focusing on the reentry capsule which is planned for MUSES-C mission. MUSES-C mission planned by ISAS is to have a rendezvous with an asteroid and to bring back its soil to Earth. Since its reentry speed is quite high (-l3 km/sec), a variety of gas-dynamical problem must be resolved.
In the present research, research effort was focused on the following main problems ; 1) the radiation efficient estimation from high temperature shock layer ahead of the vehicle, 2) the interaction of the high temperature air with the heat shield material of the vehicle, 3) the estimation of aerodynamic heat flux caused by highly-nonequilibrium high temperature shock layer. One of the main topics is the highly thermally-nonequilibrium phenomena, which is observed experimentally. This result is expected to have an impact on improving the current flow model, and to be helpful to improve the estimation accuracy by the improved flow model. Combining the results obtained from various topics, the aerodynamic heating along the flight path was successfully estimated, which was helpful to make a design requirement for such a reentry vehicle. In parallel, the possibility of the flight demonstration of such a reentry vehicle was studied.
Other than the reentry vehicle, a study was conducted on the use of penetrator system for future planetary explanation, in a gas-dynamical point of view, This system study successfully clarified a design requirement of such a penetrator system. Also, the RAM accelerator system was studied, which is useful for the transportation of the exploration result from Moon. Even in a laboratory scale, the RAM accelerator was successfully demonstrated.
Sound Generation by Interactions among Vortex, Heat and Shock Wave
Grant number：08455086 1996 - 1997
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
INOUE Osamu, HATTORI Yuuji, JU Yiguang, SASOH Akihiro, FUKUNISHI Yuu
Authorship：Coinvestigator(s)
Generation mechanism and natures of sound through vortex, heat and shock wave interactions are studied both computationally and experimentally. Inoue developped a highly-accurate, compressible Navier-Stokes code (6th-order in space and 4th-order in time) and applied it to shock-vortex interauction problems. The results show that, (1) three sounds are generated successively by the interaction between a single vortex and a plane shock wave, (2) each sound has a quadrupolar nature, and (3) the strengths of the sounds depend both on the strengths of a shock wave and a vortex. Inoue also applied the code to the interaction between a pair of vortices and a shock wave, and clarified that the number of sound generated by the interaction and the characteristic naturcs of the sounds depend on whether the pair of vortices moves in the same direction as the shock wave or opposite to it. Inoue also studied compressible flowfields around a helicopter and clarified the characteristic natures of the flowfields in a vortex ring state and in an autorotation state for the first time. The results suggest strongly that the sound generation in the helicopter rotor flowfield is closely related to the interaction between the tip-vortices and the rotor baleds. Fukunishi imposed a sound wave on a turbulent boundary layr, and examined the vortical motion in the boundary layr. Fukunishi found that the turbulent boundary layr can be effectively excited by the sound wave. Sasoh studied experimentally the sound noise at the exit of a tunnel produced by a highspeed bullet train (Shinkansen), and found that attenuation of a shock wave produced by a Shinkansen is inevitable to reduce the sound noise. Sasoh proposes the use of pseudo-perforated walls in a tunnel. By using a two-dimensional Navier-Stokes code, Ju studied numerically flowfields produced by the interaction of premixed gases of H2 and air with a shock wave, and found that the so-called Richtmyer-Meshkov instability plays an important role in the generation of vortices and thus the generation of sound. Hattori simulated numerically sound pressure fields generated by the head-on collision of two vortex rings, and found the following important results. (1) When the strengths of the two vortex rings are equal, two sounds are generated and each sound has quadrupolar nature. (2) When the strengths of the two vortex rings are not equal, four sounds are generated and the direction of the sound propagation is affected by the difference of the strengths of the two vortex rings. Hattori and lnoue also studied the characteristic natures of sound generated by oblique collisions of two vortex rings, and captured numerically the generation of octupolar sounds.
Development of a small-sized ram accelerator for improving the muzzle velocity
Grant number：08555239 1996 - 1997
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
SASOH Akihiro, KATO Yukio, TAKAYAMA Kazuyoshi
Authorship：Principal investigator
Grant amount：\9200000 （ Direct Cost: \9200000 ）
In this study, the scaling effects were analyzed by conducting quasi-one-dimensional numerical simulation with finite-rate chemical reactions being taken into account. From the numerical simulation, it was concluded that in order to obtain a wide operation regime in the thermally-choked operation mode, small-sized apparatus was favorable. Based on this, a small sized ram accelerator was constructed and its operation tests were conducted. It was found that the smaller the apparatus the more difficult its starting became. In order to better understand the starting process, flow visualization experiments were conducted. The behavior of a precursory shock wave was visualized by using a high-speed image converter camera. Density field around a projectile impinging the diaphragm at the ram acceleration tube entrance was visualized by holographic interferometry, concluding that the existing diaphragm rupture model was inadequate in quantitative numerical simulation. By varying mixture components, fill pressure, powder mass, projectile configuration, sabot configuration and the initial pressure in the pre-acceleration section, ram acceleration experiments were done, obtaining a velocity gain of 370 m/s.
STRUCTURE OF MIXING LAYER IN HIGH ENTHALPY HYPERSONIC FLOWS
Grant number：07044116 1995 - 1997
Grants-in-Aid for Scientific Research Grant-in-Aid for international Scientific Research
TAKAYAMA Kazuyoshi, SASOH Akihiro, SISLIAN Jean P.
Authorship：Coinvestigator(s)
Topics on hypersonic turbulent mixing are not only basic research topics of high speed gas dynamics but also important applications of shock wave research. This international joint research program has been carried out for three years under close sollaborations between the Shock Wave Research Center Institute of fluid Science and the Institute of Aerospace Studies University Toronto.
Results so far obtained are summarized as following :
(1) A mathematical modelling of hypersonic turbulent mixing has been obtained by establishing a finite difference scheme which can handle three-dimentional Navies-Stokes equations in unstructured grid systems.
(2) In order to include the chemical reaction terms in the above mentioned numerical scheme, detailed elementary processes of hedrogen-oxygen reactions has been investigated.
(3) In conjunction with understanding of elementary processes of hypersonic turbulent mixsing, the motion of shock waves and flows behing them has been investigated experimentally and numerically.
(4) The characteristic of a compact free piston shock tunnel and its contoured nozzle flow has investigated : piton motion in compression tube ; starting process of nozzle fow ; effect of diaphragm location on the nozzle flows ; Pitt pressure profile of nozzle flow ; driver gas contamination. Based upon these results, it is found that the contoured Mach 6 nozzle has a very limited working region so that a conical nozzle is designed for its replacement.
(5) The stagnation enthalpy of 14 MA/kg and nozzle flow Mach number of 6 has been obtained. Double exposure holographic interferometric observation has been successfully applied to the flow over a cylinder.
(6) The results have been obtained under close collaboration during the stay of Professor Jean Sislian for total 8 months from the fiscal years 1995 to 1997 and also the stay of Mr.Jurgen Schumacher for 6 month in 1997.
(7) The results so far obtained are submitted for the publication in international journals having high reputation.
Study on effects of chemical reaction rates on ram accelerator thrust performance
Grant number：07651118 1995 - 1996
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\2500000 （ Direct Cost: \2500000 ）
Numerical analyzes and ram accelerator operation experiments were conducted with the aim of clarifying relationships between its thrust performance and chemical reaction rates. There exist two propulsive modes in which subsonic combustion occurs ; subdetonative and transdetonative modes. In this study, numerical analyzes were based on quasi-one-dimensional steady flow with finite-rate chemistry taken into account. The formulation yields ordinal differential equations solution of which can be obtained through a well-developed implicit method. Instability in the calculation due to sonic singularity was avoided by a method which was developed uniquely in this study. The analyzes shows a propulsive mode is determined by the relationship between a characteristic length of finite-rate chemical reactions and a projectile length ; in a large apparatus the transdetonative propulsive mode tends to appear at relatively low Mach numbers. This result suggests that a small apparatus has an advantage to obtain stable subdetonative mode. For a large apparatus, a similar operation is possible by adjusting the fill pressure of the mixture. The experiments were conducted using a world-smallest working ram accelerator with a 25-mm-bore. As was predicted by the analyzes, ram acceleration was realized with a relatively energetic mixture. This study points out the importance of a chemical reaction induction length in determining the thrust performance. This conclusion should lead to further development of quantitative clarification of the scaling laws on ram accelerators.
Study of Acoustic Sounds by Computational and Experimental Fluid Dynamics
Grant number：06452172 1994 - 1995
Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (B)
INOUE Osamu, TSUBOTA Makoto, SASOH Akihoro, HAYASE Toshiyuki
Authorship：Coinvestigator(s)
Acoustic sounds observed in four different fields of fluid dynamics are studied by four experts independently. Each expert in a field is supported by the other three experts in other fields who have different ideas, methods, know-hows and experiences, respectively. Inoue studied sounds produced by vortex-vortex interactions and shock wave-vortex interactions by 2D/3D direct Navier-Stokes simulations, and clarified the quadrupolar natures of sounds by the interactions. He also studied the 3D compressible flows around helicopter rotors and captured numerically vortex ring states and auto-rotation states for first time which are closely related to helicopter noises. Hayase studied numerically unsteady 2D flows in an orifice and also through spool valves, and showed that acoustic sound produced in these flows are closely related to the behavior of vortices. Sasoh studied experimentally tunnel sonic booms produced by highspeed trains, and showed that the booms are directly related to shock waves generated by entrance of a train in a long tunnel. Tsubota studied acoustic sounds in superfluid Helium and clarified that generation of quantized vortices is one of the sources of sounds in low temperature flow fields. The results obtained by the four experts are compared with each other. It is found that there are common natures among the sounds observed in spite of the difference of the flow fields studied ; for example, sounds produced by vortex-vortex interactions and vortex-sounds interactions have quadrupolar natures while dipolar property is predominant when obstacles or walls exist.
Fundamental and Applicational Investigation of Ram Accelerator
Grant number：05402033 1993 - 1995
Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (A)
TAKAYAMA Kazuyoshi, SASOH Akihiro, INOUE Osamu, NIOKA Takashi
Authorship：Coinvestigator(s)
A ram accelerator system has been developed. The test section has a 25 mm bore and a 6m length. Its preaccelerator, a powder gun, is capable of launching a 40-gram payload to 1.2km/s with smokeless powder of 30 grams. The mixture supply system, composed of mass flow controllers and backpressure regulators, is easy to handle and utilizes cylinder pases up to a pressure about 1MPa higher than the fill pressure. Projectile velocity is measured by sensing magnetic induction using home made pick-up coils. The multiplexer system is capable of recording pressure data at plural points in one channel.
Sixty ram acceleration experiments were made with methane-oxygen-nitrogen (or argon) mixtures. Sabot separation was made only by unsteady gas dynamics made in the mixture. Starting condition for ram acceleration strongly depended on non-dimensional heat release, entry speed and sabot design.
A numerical code which can calculate the thrust performance based on the existing ram accelerator Hugoniot theory has been developed. Moreover, the theory was extended by taking finite-rate chemistry into account. With the extended theory, performances not only of the thermally choked mode but also of the transdetonative mode can be analyzed.
It is important through this research project to show that ram acceleration is possible with this small bore apparatus, thereby enhancing understandings of scaling effects of ram accellerators. This technology is promising in being applied to space technology, material technology etc. in Japan.
INVESTIGATION OF INTERNAL MECHANISM OF ELECTRIC THRUSTERS AND THEIR PERFORMANCE ANALYSIS
Grant number：04302025 1992 - 1994
Grants-in-Aid for Scientific Research Grant-in-Aid for Co-operative Research (A)
ARAKAWA Yoshihiro, TOKI Kyoichiro, KIMURA Itsuro, FUJIWARA Toshitaka, NISHIDA Michio, YOSHIKAWA Takao
Authorship：Coinvestigator(s)
In electric propulsion, there are several kinds of electric thrusters, such as electrostatic type, electromagnetic type and electrothermal type. The drawbacks common to the thrusters are ; 1)low energy conversion efficiency, 2)not demonstrated endurability for long operation, and 3)not obtained scaling laws determining thruster performance. To overcome these drawbacks, it is necessary to investigate physical phenomena in thrusters, Such-as ionization and dissociation processes, plasma acceleration mechanism, and heat and energy transport processes, not only by theoretical analysis but also by experimental one.
For this purpose, this study has been continued for three years since 1992. It was a co-operative work of researchers and engineers of universities and research institutes, and had joint-meetings for several times, exchanging informations and discussing research contents and current topics.
As the resuit, it was concluded that ; 1) in ion thrusters, numerical code has been constructed, which can be used to estimate thruster performance for given geometrical design and operating parameters, 2) as for arcjet thrusters, arc dischrage behaviors were examined and clarified both by experimental observations and by numerical calculations, 3) MPD flow analyzes have been conducted to obtain a further understanding of the relations between plasma flow and arc discharge, indicating that non-equilibrium flow plays an important role on inoization and plasma acceleration processes.
Development of scaling law for radiative heat transfer from high enthelpyshock layrs
Grant number：04650051 1992 - 1993
Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (C)
SASOH Akihiro
Authorship：Principal investigator
Grant amount：\2000000 （ Direct Cost: \2000000 ）
Radiative heat transfer from non-equilibrium, high-enthalpy shock layrs generated around a blunt body has been studied. At Mach numbers from 25 to 35, the radiative heat transfer is mainly caused by strong radiative emission in a thermally and chemically non-equilibrium layr generated immediately behind the shock wave. According as an upstream Mach number increase, the intensity of the radiative emission sharply increases, resulting in sharp increase in the radiativeheat transfer. Under the above-mentioned condition, the thickness of the strong emission layr is almost independent of the nose radius. Hence, the radiative heat transfer is almost unchanged with the radius at such a low Mach number levels. At higher Mach number levels, radiative emission from a high-electron-density region near the wall become dominant. In this case, the radiative heat transfer increases with the dimensions of the body.
Grant number：04222110 1992
科学研究費助成事業 重点領域研究
藤井 直之, 谷口 宏充, 佐宗 章弘
Authorship：Coinvestigator(s)
自然界の中でも最も大規摸な衝撃波現象の一つに爆発的噴水に伴う火山性ブラストがある。本研究では、火山性ブラストによる爆風圧やその伝播の把握のために、遠隔的に設置できかつ記録が可能な測定系、すなわち投下型・全方位指向性の爆風圧検出器について、実際の火山性ブラスト現象を解明するための計測法を確立するのを目的として共同研究を開始した。そのため、これまで衝撃波工学センターで開発され実用化されてきたピエゾセンサーによる圧力計を改良し、噴火口近傍でも設置でき測定可能な火山性ブラスト用の計測法の開発を行うことが、十分可能でかつ緊急の課題であると考えた。とくに火山性ブラストは、高温のガスと火山灰・噴石破片の混合物からなり、しかもその継続時間が通常の実験室内の衝撃波とは比較にならないほど長いと考えられるので、特別な工夫を必要とする。実用性のある火山性ブラスト用の計測系は、衝撃波の到来方向に無関係に設置できかつ安価・簡便なこと、耐熱性がありデータの記録を遠隔的にできることなどが必要条件である。本研究によって、まだ多少の改良点が必要ではあるが、このような条件に適合した十分実用に耐えうる圧力センサーと記録システムの開発見通しがたった。圧力センサーとしては、PVDFピエゾフィルムを貼ったステンレス製円筒の末端部の厚みによって、測定圧力範囲を調節できるものである。また、記録システムはSRAMに常時記録されたデータから、一定時間毎にトリガーレベル以上の信号を検出しDRAMにイベント毎に記録する方式が最適であると判断し、現在このシステムの試験をかねて、雲仙岳周辺で観測を行っている。今後は、さらに消費電流を少なくし、かつ簡便に設置できるシステムとデータの読みだしにテレメータ方式を採用する事など検討していく予定である。
Grant number：02252109 1990
科学研究費助成事業 重点領域研究
藤原 俊隆, 佐宗 章弘, 久保田 弘敏, 斉藤 昊, 松為 宏幸
Authorship：Coinvestigator(s)
デトネ-ションの研究に関しては、(i)斜めデトネ-ションの安定性と周期的振動の機構解明、(ii)逆制動ふく射を伝播機構とするレ-ザ-・デトネ-ションの可能性が調ベられた。これらは簡単化された化学反応に基いて解析された為、実際の現象が推測に基く機構から物理化学的に生じるかどうか、解析の結果は定性的に納得のゆく結論へ導く。即ち斜めデトネ-ションの振動は、局所的な爆発と壁から反射する圧力波間の相互干渉による共鳴現象である。炭酸ガスレ-ザ-を、水素分子やアルゴンガス中に、一平方ミリ当り10メガワットの強度で集光すると、球面レ-ザ-・デトネ-ションが伝播しそうである。
衝撃波後方において、アセトアルドキシム及びホルムアルドキシムを熱分解し、生成物の挙動を調べた。二段階の単分子反応が起こる場合に、一段階目の反応の非平衡遷移状態構造が、二段階目の反応経路の選択を支配すると言う考えと同様に、分子の異性化についても検討がなされた。実験と反応分子動力学的計算の双方から、この事は言えそうである。
その他松為、藤井、山崎らは、多くのラジカル反応に関して、衝撃波後方の高温下における、高速連鎖反応存在下に、速度定数を良い精度で計測した。この手法により、この迄全くと言っても良い程に手のつけられなかったラジカル反応が解明され、燃焼現象の制御や公害汚染物質の抑制に役立つ研究が行われる可能性を与えている。
アルコール－硝安発射薬
佐宗章弘、高山和喜、生田一成、永易伸生、大坪信武
宇宙推進工学
2021
航空宇宙推進工学
2020
Introduction to System Engineering
2016
Introduction to System Engineering
2015
Introduction to System Engineering
2014
Introduction to System Engineering
2013
Introduction to System Engineering
2012
Introduction to Production Engineering
2011
Introduction to System Engineering
2011
