H. Ozawa, K. Hanai, K. Kitamura, K. Mori, Yoshiaki Nakamura
A small crack on body surface led to a tragic accident in 2003, which is the Columbia accident. During the shuttle's re-entry, high temperature gas penetrated crack on leading-edge of the left wing and melted the aluminum structure, finally the Columbia blew up. Since early times, there are many fundamental studies about simple cavity-flow formed on body surface in hypersonic speeds. However, an investigation of Shock/Boundary-Layer Interaction (SBLI) on crack has not been researched. For multistage space transportation vehicle such as TSTO, SBLI is an inevitable problem, and then SBLI on crack becomes a critical issue for TSTO development. In this study, the effects of crack, where SBLI occurs, were investigated for TSTO hypersonic speed (M∞ = 8.1). A square crack locates at SBLI point on the TSTO booster. Results show that a crack and its depth strongly effect on peak heat flux and aerodynamic interaction flow-field. In the cases of shallow crack (d/C ≤ 0.10), there exist two high heat flux regions on crack floor, which locates at a flow reattachment region and a back end wall of crack. In this case, a peak heat flux at flow reattachment region becomes about 2 times as large as the stagnation point heat flux, which value becomes larger compared with a peak heat flux in the case of No-Crack TSTO. While in the case of deep crack (d/C = 0.20), overall heat flux on crack floor decreases to below the stagnation point heat flux. These results provide useful data for a development of TSTO thermal protection system (TPS) such as thermal protection tile.
{"title":"Effects of Crack on Heat Flux in Hypersonic Shock/Boundary-Layer Interaction","authors":"H. Ozawa, K. Hanai, K. Kitamura, K. Mori, Yoshiaki Nakamura","doi":"10.2322/JJSASS.58.68","DOIUrl":"https://doi.org/10.2322/JJSASS.58.68","url":null,"abstract":"A small crack on body surface led to a tragic accident in 2003, which is the Columbia accident. During the shuttle's re-entry, high temperature gas penetrated crack on leading-edge of the left wing and melted the aluminum structure, finally the Columbia blew up. Since early times, there are many fundamental studies about simple cavity-flow formed on body surface in hypersonic speeds. However, an investigation of Shock/Boundary-Layer Interaction (SBLI) on crack has not been researched. For multistage space transportation vehicle such as TSTO, SBLI is an inevitable problem, and then SBLI on crack becomes a critical issue for TSTO development. In this study, the effects of crack, where SBLI occurs, were investigated for TSTO hypersonic speed (M∞ = 8.1). A square crack locates at SBLI point on the TSTO booster. Results show that a crack and its depth strongly effect on peak heat flux and aerodynamic interaction flow-field. In the cases of shallow crack (d/C ≤ 0.10), there exist two high heat flux regions on crack floor, which locates at a flow reattachment region and a back end wall of crack. In this case, a peak heat flux at flow reattachment region becomes about 2 times as large as the stagnation point heat flux, which value becomes larger compared with a peak heat flux in the case of No-Crack TSTO. While in the case of deep crack (d/C = 0.20), overall heat flux on crack floor decreases to below the stagnation point heat flux. These results provide useful data for a development of TSTO thermal protection system (TPS) such as thermal protection tile.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"295 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127003906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-pressure air micro-plasmajets with a length of 10mm were generated through a nozzle with a diameter of 0.7mm at the pressures of 31.3 and 5.3kPa. Spectroscopic measurements were conducted at the point of 0.5mm from the nozzle exit on the central axis. The N2+ 1- and N2 2+ bands were predominant in the wavelength region of 280 to 420nm and the band shape was almost independent of the pressure. From temperature determination by a spectral matching method, it was found that the plasmajets were in a thermal nonequilibrium state and that vibrational temperature was much higher than rotational one. The experimental intensity distribution was reconstructed by the equilibrium radiation theory, in good agreement except for the N2 2+ bands with v′ ≥ 2 as in case of atmospheric air micro-plasmajet. For these bands, much better agreement was obtained by taking the effects of predissociation and non-Boltzmann rotational population distribution for N2C3Πu state into consideration in the theory. Discussions were made about potential cause of high vibrational temperature and slight difference between experimental and theoretical band shapes of the N2 2+ bands at the low-pressures.
{"title":"低圧空気極小プラズマジェットのノズル出口直後における N2 2+バンドの放射特性","authors":"健二 澁澤, 賢人 舩津, 紘行 白井, 聖子 久保田","doi":"10.2322/JJSASS.58.1","DOIUrl":"https://doi.org/10.2322/JJSASS.58.1","url":null,"abstract":"Low-pressure air micro-plasmajets with a length of 10mm were generated through a nozzle with a diameter of 0.7mm at the pressures of 31.3 and 5.3kPa. Spectroscopic measurements were conducted at the point of 0.5mm from the nozzle exit on the central axis. The N2+ 1- and N2 2+ bands were predominant in the wavelength region of 280 to 420nm and the band shape was almost independent of the pressure. From temperature determination by a spectral matching method, it was found that the plasmajets were in a thermal nonequilibrium state and that vibrational temperature was much higher than rotational one. The experimental intensity distribution was reconstructed by the equilibrium radiation theory, in good agreement except for the N2 2+ bands with v′ ≥ 2 as in case of atmospheric air micro-plasmajet. For these bands, much better agreement was obtained by taking the effects of predissociation and non-Boltzmann rotational population distribution for N2C3Πu state into consideration in the theory. Discussions were made about potential cause of high vibrational temperature and slight difference between experimental and theoretical band shapes of the N2 2+ bands at the low-pressures.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129291809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates wing aerodynamic characteristics used for bi-plane micro-air vehicles. Surface pressure distributions of two-dimensional biplane airfoils (4% cambered-plate airfoil) were measured at a chord Reynolds number of 6.4 × 10. Lift characteristics of three-dimensional biplane rectangular wings (aspect ratio of 3) were also measured at the same Reynolds number. It was indicated that the behaviors of laminar separation bubble formed both on the upper and lower airfoils/wings affects their lift characteristics. Bi-plane wings with positive stagger, i.e. protruded upper wing indicated higher maximum lift coefficient. This is caused by different behaviors of laminar separation bubble
{"title":"Experimental Study on the Wing Lift Characteristics of Biplane Micro Air Vehicle","authors":"Kohei Akiyama, A. Tezuka, Y. Sunada, K. Rinoie","doi":"10.2322/JJSASS.57.476","DOIUrl":"https://doi.org/10.2322/JJSASS.57.476","url":null,"abstract":"This paper investigates wing aerodynamic characteristics used for bi-plane micro-air vehicles. Surface pressure distributions of two-dimensional biplane airfoils (4% cambered-plate airfoil) were measured at a chord Reynolds number of 6.4 × 10. Lift characteristics of three-dimensional biplane rectangular wings (aspect ratio of 3) were also measured at the same Reynolds number. It was indicated that the behaviors of laminar separation bubble formed both on the upper and lower airfoils/wings affects their lift characteristics. Bi-plane wings with positive stagger, i.e. protruded upper wing indicated higher maximum lift coefficient. This is caused by different behaviors of laminar separation bubble","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"46 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132640075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present study the deformation and motion of a parachute in the process of inflation are simulated by applying the immersed boundary technique in a fluid-structure coupling solver. It was found from simulated results that the canopy is first inflated in the normal direction to the uniform flow (in the lateral direction), and then its apex is pulled by a vortex ring generated near the canopy’s outer surface due to its negative pressure. After the end of this inflation process, the canopy moves in the tangential direction to the spherical surface, the center of which is located at the payload location. This motion is caused by the breakup of an initial axisymmetric vortex, where many vortices are generated from the shear layer. The predicted maximum parachute opening force is twice as large as the payload force in the steady state, which is in good agreement with experiment.
{"title":"Numerical Simulation of Parachute Inflation Process by IB Method","authors":"M. Miyoshi, K. Mori, Yoshiaki Nakamura","doi":"10.2322/JJSASS.57.419","DOIUrl":"https://doi.org/10.2322/JJSASS.57.419","url":null,"abstract":"In the present study the deformation and motion of a parachute in the process of inflation are simulated by applying the immersed boundary technique in a fluid-structure coupling solver. It was found from simulated results that the canopy is first inflated in the normal direction to the uniform flow (in the lateral direction), and then its apex is pulled by a vortex ring generated near the canopy’s outer surface due to its negative pressure. After the end of this inflation process, the canopy moves in the tangential direction to the spherical surface, the center of which is located at the payload location. This motion is caused by the breakup of an initial axisymmetric vortex, where many vortices are generated from the shear layer. The predicted maximum parachute opening force is twice as large as the payload force in the steady state, which is in good agreement with experiment.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125030555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"低Re数領域でのNACA0012翼まわりの流れ場 : 第1報 翼後流の特性","authors":"Tomohisa Ohtake, Tatsuo Motohashi","doi":"10.2322/JJSASS.57.397","DOIUrl":"https://doi.org/10.2322/JJSASS.57.397","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121093476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The coupled rotation-vibration-dissociation analysis of carbon monoxide is conducted by the state-resolved direct simulation Monte-Carlo (DSMC) model incorporated with a quasi-classical trajectory (QCT) model for computation of inter-molecular collision dynamics. The potential energy surface for the triatomic system is described by the London-Eyring-Polanyi-Sato (LEPS) potential, which is determined from the spectroscopic constants of diatomic molecules and the results of ab initio electronic structure calculations. A comparison is made between the numerical results and the experimental data in terms of the macroscopic relaxation parameters and the dissociation rate coefficients at moderate temperatures. Finally, the relaxation parameters and the dissociation rate coefficients at extremely high temperatures where the experimental data are unavailable have been estimated by the DSMC-QCT calculations.
{"title":"CO-O衝突によるCOの内部モード緩和と解離のDSMC-QCT解析","authors":"和央 藤田","doi":"10.2322/JJSASS.57.405","DOIUrl":"https://doi.org/10.2322/JJSASS.57.405","url":null,"abstract":"The coupled rotation-vibration-dissociation analysis of carbon monoxide is conducted by the state-resolved direct simulation Monte-Carlo (DSMC) model incorporated with a quasi-classical trajectory (QCT) model for computation of inter-molecular collision dynamics. The potential energy surface for the triatomic system is described by the London-Eyring-Polanyi-Sato (LEPS) potential, which is determined from the spectroscopic constants of diatomic molecules and the results of ab initio electronic structure calculations. A comparison is made between the numerical results and the experimental data in terms of the macroscopic relaxation parameters and the dissociation rate coefficients at moderate temperatures. Finally, the relaxation parameters and the dissociation rate coefficients at extremely high temperatures where the experimental data are unavailable have been estimated by the DSMC-QCT calculations.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123928863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Sakai, Yusuke Sonoda, Katsu Kakiuchi, Y. Sugiyama, Hisayoshi Honda, Kohei Moribe, M. Chiba, Yosuke Nakamura
The paper reports the vibration characteristics assessment of grid panels which were furnished in the main structure of 50kg-class micro-satellite ``SOHLA-1''. Three different types of grid panels with dimensions of 141.1 × 423.0 × 10.0mm, triangle-grid-type panel, rectangle-grid-type panel and frame-type panel, were investigated to find their dynamics through impulse test. Vibration characteristics were also simulated by a FEM computer soft NASTRAN. Application of flame-retardant type magnesium alloy to the panel was made to confirm the structural effectiveness of magnesium alloy panel.
{"title":"Vibration Characteristics Assessment of External Store Panels Furnished in a 50kg-Class Micro-Satellite ``SOHLA-1''","authors":"T. Sakai, Yusuke Sonoda, Katsu Kakiuchi, Y. Sugiyama, Hisayoshi Honda, Kohei Moribe, M. Chiba, Yosuke Nakamura","doi":"10.2322/JJSASS.57.415","DOIUrl":"https://doi.org/10.2322/JJSASS.57.415","url":null,"abstract":"The paper reports the vibration characteristics assessment of grid panels which were furnished in the main structure of 50kg-class micro-satellite ``SOHLA-1''. Three different types of grid panels with dimensions of 141.1 × 423.0 × 10.0mm, triangle-grid-type panel, rectangle-grid-type panel and frame-type panel, were investigated to find their dynamics through impulse test. Vibration characteristics were also simulated by a FEM computer soft NASTRAN. Application of flame-retardant type magnesium alloy to the panel was made to confirm the structural effectiveness of magnesium alloy panel.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114388782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper addresses the design problem of Gust Alleviation (GA) flight controllers for linearized longitudinal aircraft motions with some uncertainties using prior turbulence information via Model Predictive Control (MPC) scheme. Considering that the plant uncertainties are assumed to be modeled as time-invariant uncertain but bounded delays at the plant control input, we derive a plant set, the number of whose elements are finite, to represent the uncertainties without introducing any approximations. For this set, we derive a new formulation to obtain an optimal control input, which guarantees some robust performance with respect to GA performance against the delays, as a Second-Order Cone Programming (SOCP) problem. As the conditions in SOCP problems have the convexity with respect to the decision variables, the global optimal control input for our addressed problem is obtained using some effective software. Exploiting that our proposed method introduces no approximations when deriving the plant set and SOCP problems can give the global optima, we propose a method to identify whether or not the prior gust information improves GA performance. A numerical example which illustrates our conclusions is included.
{"title":"乱気流の事前情報を用いたロバストモデル予測制御による Gust Alleviation 制御","authors":"昌之 佐藤, 信宏 横山, 淳二 佐藤","doi":"10.2322/JJSASS.57.345","DOIUrl":"https://doi.org/10.2322/JJSASS.57.345","url":null,"abstract":"This paper addresses the design problem of Gust Alleviation (GA) flight controllers for linearized longitudinal aircraft motions with some uncertainties using prior turbulence information via Model Predictive Control (MPC) scheme. Considering that the plant uncertainties are assumed to be modeled as time-invariant uncertain but bounded delays at the plant control input, we derive a plant set, the number of whose elements are finite, to represent the uncertainties without introducing any approximations. For this set, we derive a new formulation to obtain an optimal control input, which guarantees some robust performance with respect to GA performance against the delays, as a Second-Order Cone Programming (SOCP) problem. As the conditions in SOCP problems have the convexity with respect to the decision variables, the global optimal control input for our addressed problem is obtained using some effective software. Exploiting that our proposed method introduces no approximations when deriving the plant set and SOCP problems can give the global optima, we propose a method to identify whether or not the prior gust information improves GA performance. A numerical example which illustrates our conclusions is included.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132924079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Tsuboi, Yuichiro Kimura, A. Hayashi, E. Yamada, V. Tangirala
The propulsive performance was estimated for the H2/Air PDE with a convergingdiverging exhaust nozzle using multi-cycle two-dimensional limit cycle simulations with the detailed chemical reaction model. The present simulation also compared with a variable property model reported in the literature. The overall features such as the effects of filling fraction, nozzle configuration, and flight condition in the present results are in agreement. The present results show that optimum rth/rtube for Ispf are 0.6 and 0.5 for M=2.1 and 3.5, respectively.
{"title":"Numerical Study and Performance Evaluation for Pulse Detonation Engine with Exhaust Nozzle","authors":"N. Tsuboi, Yuichiro Kimura, A. Hayashi, E. Yamada, V. Tangirala","doi":"10.2322/JJSASS.58.91","DOIUrl":"https://doi.org/10.2322/JJSASS.58.91","url":null,"abstract":"The propulsive performance was estimated for the H2/Air PDE with a convergingdiverging exhaust nozzle using multi-cycle two-dimensional limit cycle simulations with the detailed chemical reaction model. The present simulation also compared with a variable property model reported in the literature. The overall features such as the effects of filling fraction, nozzle configuration, and flight condition in the present results are in agreement. The present results show that optimum rth/rtube for Ispf are 0.6 and 0.5 for M=2.1 and 3.5, respectively.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127792487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"鈍頭物体周りにおけるプラズマ流れのMHD Flow Controlに及ぼす イオンスリップ効果の影響","authors":"智之 吉野, 諒 榊原, 貴康 藤野, 本雄 石川","doi":"10.2322/JJSASS.57.280","DOIUrl":"https://doi.org/10.2322/JJSASS.57.280","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131565476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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