Spectroscopic measurements of microwave-discharged low-pressure nitrogen plasmas were made in a tube with a diameter of 9.5mm and length of 42mm. Intense radiation of N2 2+ bands and weak radiations of N2+ 1-, N2 1+, and NO γ bands were observed. Unique intensity distribution of N2 2+ bands with high vibrational levels was observed as in the arc-discharged micro-air plasma-jets. Rotational and vibrational temperatures were determined by a spectral matching method with N2 2+ (0, 2) and (1, 3) bands. The vibrational state of the plasma was also investigated by the N2 2+ band intensity. As the experimental spectra could not be reconstructed by a usual equilibrium radiation theory with one rotational temperature, the theoretical spectra were constructed with the effects of predissociation and theoretical non-Boltzmann rotational population distribution, and were compared with the experimental ones. As a result, it was found that the vibrational and rotational temperatures were dependent on the theoretical model for rotational population distribution, that the rotational temperature was dependent on the vibrational states, and that the plasmas were in the vibrational non-equilibrium state.
{"title":"低圧マイクロ波放電プラズマのN2 2+バンドの放射と温度特性","authors":"健二 澁澤, 賢人 舩津, 紘行 白井, 文雄 高草木","doi":"10.2322/JJSASS.55.232","DOIUrl":"https://doi.org/10.2322/JJSASS.55.232","url":null,"abstract":"Spectroscopic measurements of microwave-discharged low-pressure nitrogen plasmas were made in a tube with a diameter of 9.5mm and length of 42mm. Intense radiation of N2 2+ bands and weak radiations of N2+ 1-, N2 1+, and NO γ bands were observed. Unique intensity distribution of N2 2+ bands with high vibrational levels was observed as in the arc-discharged micro-air plasma-jets. Rotational and vibrational temperatures were determined by a spectral matching method with N2 2+ (0, 2) and (1, 3) bands. The vibrational state of the plasma was also investigated by the N2 2+ band intensity. As the experimental spectra could not be reconstructed by a usual equilibrium radiation theory with one rotational temperature, the theoretical spectra were constructed with the effects of predissociation and theoretical non-Boltzmann rotational population distribution, and were compared with the experimental ones. As a result, it was found that the vibrational and rotational temperatures were dependent on the theoretical model for rotational population distribution, that the rotational temperature was dependent on the vibrational states, and that the plasmas were in the vibrational non-equilibrium state.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126463247","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 design of a wave rotor requires an understanding of the pressure wave dynamics in the rotor passages. The present paper describes a two-dimensional numerical simulation and an experimental visualization of the wave rotor compression process. First, a unique experimental apparatus with fixed cells and rotating ports was constructed for visualization and direct measurements; this arrangement is opposite to the conventional setup. Next, experimental and numerical results were compared to verify the simulation modelling, particularly with regard to the propagation velocity of pressure waves in the passages. Lastly, the effects of gradually opening the passage to the ports and leakage through the clearance, which are considered to be dominant factors in wave rotor operation, on the pressure wave dynamics were carefully investigated. The results showed that the gradual passage opening greatly influences the primary shock wave, whereas the leakage mostly influences the secondary (reflected) shock wave. Moreover, it was revealed that the leakage generates an extra pressure wave during the compression process due to the interaction between adjacent passages.
{"title":"Visualization of Wave Rotor Inner Flow Dynamics","authors":"K. Okamoto, T. Nagashima, K. Yamaguchi","doi":"10.2322/JJSASS.54.345","DOIUrl":"https://doi.org/10.2322/JJSASS.54.345","url":null,"abstract":"The design of a wave rotor requires an understanding of the pressure wave dynamics in the rotor passages. The present paper describes a two-dimensional numerical simulation and an experimental visualization of the wave rotor compression process. First, a unique experimental apparatus with fixed cells and rotating ports was constructed for visualization and direct measurements; this arrangement is opposite to the conventional setup. Next, experimental and numerical results were compared to verify the simulation modelling, particularly with regard to the propagation velocity of pressure waves in the passages. Lastly, the effects of gradually opening the passage to the ports and leakage through the clearance, which are considered to be dominant factors in wave rotor operation, on the pressure wave dynamics were carefully investigated. The results showed that the gradual passage opening greatly influences the primary shock wave, whereas the leakage mostly influences the secondary (reflected) shock wave. Moreover, it was revealed that the leakage generates an extra pressure wave during the compression process due to the interaction between adjacent passages.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130909314","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 study proposes a new approach to estimating micro-debris distribution from solar array images. In Geosynchronous Earth Orbit (GEO), enough debris measurement has not been done because of long distance from the Earth to the orbit. On the other hand, most of the satellites have solar panels as an indispensable power source, and they become the reasonable target of micro-debris and cosmic dust. From diameters of impact craters on the surfaces of the solar arrays the debris’ size distribution can be estimated with Bayesian approach, whereas the real shapes of the impact craters from the camera images arbitrarily taken from slant views should be obtained. We apply projective invariant properties to the original images to recover the images taken from front views which similarly express the real shapes of the craters. The effectiveness of the proposed method is demonstrated by a series of the numerical simulations using artificial camera images.
{"title":"A New Approach to Estimating Micro-Debris’ Size Distribution from Solar Array Images","authors":"Koki Fujita, H. Hirayama, T. Hanada","doi":"10.2322/JJSASS.54.527","DOIUrl":"https://doi.org/10.2322/JJSASS.54.527","url":null,"abstract":"This study proposes a new approach to estimating micro-debris distribution from solar array images. In Geosynchronous Earth Orbit (GEO), enough debris measurement has not been done because of long distance from the Earth to the orbit. On the other hand, most of the satellites have solar panels as an indispensable power source, and they become the reasonable target of micro-debris and cosmic dust. From diameters of impact craters on the surfaces of the solar arrays the debris’ size distribution can be estimated with Bayesian approach, whereas the real shapes of the impact craters from the camera images arbitrarily taken from slant views should be obtained. We apply projective invariant properties to the original images to recover the images taken from front views which similarly express the real shapes of the craters. The effectiveness of the proposed method is demonstrated by a series of the numerical simulations using artificial camera images.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"48 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125908625","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}
Cyclic zero-tension tests for symmetric angle-ply CFRP laminated specimens were carried out to investigate the low cycle fatigue behavior of graphite/epoxy and graphite/PEEK composites. Two types of stacking sequences were tested: [+θ/-θ]4s (Distributed ply) and [+θ4/-θ4]s (Blocked ply), where θ was 30o or 45o. Stress-strain curves of specimens under cyclic loadings were obtained by means of an extensometer. A mechanical ratcheting, which means progressive increase in plastic strain at each cycle, was observed on the cyclic stress-strain curves. Comparing the stress-strain curve of static tensile test with one of the cyclic zero-tension test, we made the assumption that the fatigue failure occurred when the ratcheting strain by cyclic loadings reached the static failure strain. Results of an ultrasonic scanning test revealed that the distributed ply specimens differed from the blocked ply specimens in an internal fatigue damage progress.
{"title":"Experimental Observation on Low Cycle Fatigue Behavior of Symmetric Angle-Ply CFRP Laminate","authors":"M. Sakai, N. Uda, K. Kunoo","doi":"10.2322/JJSASS.54.555","DOIUrl":"https://doi.org/10.2322/JJSASS.54.555","url":null,"abstract":"Cyclic zero-tension tests for symmetric angle-ply CFRP laminated specimens were carried out to investigate the low cycle fatigue behavior of graphite/epoxy and graphite/PEEK composites. Two types of stacking sequences were tested: [+θ/-θ]4s (Distributed ply) and [+θ4/-θ4]s (Blocked ply), where θ was 30o or 45o. Stress-strain curves of specimens under cyclic loadings were obtained by means of an extensometer. A mechanical ratcheting, which means progressive increase in plastic strain at each cycle, was observed on the cyclic stress-strain curves. Comparing the stress-strain curve of static tensile test with one of the cyclic zero-tension test, we made the assumption that the fatigue failure occurred when the ratcheting strain by cyclic loadings reached the static failure strain. Results of an ultrasonic scanning test revealed that the distributed ply specimens differed from the blocked ply specimens in an internal fatigue damage progress.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124740223","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}
Pub Date : 2006-09-05DOI: 10.14822/KJSASS.54.632_281
丸山 謙一郎
{"title":"学生による学生のための「学生交流会」 : 鳥人間チーム","authors":"丸山 謙一郎","doi":"10.14822/KJSASS.54.632_281","DOIUrl":"https://doi.org/10.14822/KJSASS.54.632_281","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124184662","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}
Both experiment and calculation demonstrated to clarify the effect of a column wall jet in uniform fluid flow on the characteristic of wake oscillation. The vortex intensity decreased and the oscillations attenuated when the jet direction matched the uniform flow. When the jet flow was reversed, the vortex intensity grew and the oscillations increased in magnitude. It has been found that the Strouhal number based on the half width of the flow velocity distribution was nearly constant. Also, the frequency depended on the vortex structure of the wake, which was further dependent on the jet flow velocity. In addition, the situations that gave twin peaks in the oscillation spectrum were found both in experiment and in calculation.
{"title":"Wake Oscillation of Column Wall Jet in Uniform Flow","authors":"Yohei Yoshida, Kotaro Sato, Yōichi Ono","doi":"10.2322/JJSASS.54.288","DOIUrl":"https://doi.org/10.2322/JJSASS.54.288","url":null,"abstract":"Both experiment and calculation demonstrated to clarify the effect of a column wall jet in uniform fluid flow on the characteristic of wake oscillation. The vortex intensity decreased and the oscillations attenuated when the jet direction matched the uniform flow. When the jet flow was reversed, the vortex intensity grew and the oscillations increased in magnitude. It has been found that the Strouhal number based on the half width of the flow velocity distribution was nearly constant. Also, the frequency depended on the vortex structure of the wake, which was further dependent on the jet flow velocity. In addition, the situations that gave twin peaks in the oscillation spectrum were found both in experiment and in calculation.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129645632","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 proposes a Hybrid Genetic Algorithm (Hybrid-GA) which is suitable for a large scale multidisciplinary optimization problem such as Two-Stage-To-Orbit (TSTO) spaceplane optimal design problem. The Hybrid-GA is implemented by combining Sequential Quadratic Programming (SQP) method with GA. When constructing the Hybrid-GA, there are three problems that should be solved; 1) decision of optimized variables and discrete method, 2) how to use results of local search, and 3) selection for survival method. These problems are discussed and solved in order to effectively combine SQP method with GA. In order to demonstrate the effectiveness of the proposed Hybrid-GA, the TSTO spaceplane optimal design problem, which consists of weight, aerodynamics, propulsion, and flight trajectory analyses, is investigated using the proposed Hybrid-GA, and the optimal results of Hybrid-GA are compared with that of Simple-GA, and SQP methods. Finally, strategy to achieve the TSTO spaceplane is proposed by comparing the optimal results of changing payload weight and maximum wing load factor of booster.
{"title":"Hybrid-GA を用いた二段式スペースプレーンの最適設計","authors":"今村 俊介, 小島 広久, 土屋 武司, 弘敏 久保田","doi":"10.2322/JJSASS.54.279","DOIUrl":"https://doi.org/10.2322/JJSASS.54.279","url":null,"abstract":"This paper proposes a Hybrid Genetic Algorithm (Hybrid-GA) which is suitable for a large scale multidisciplinary optimization problem such as Two-Stage-To-Orbit (TSTO) spaceplane optimal design problem. The Hybrid-GA is implemented by combining Sequential Quadratic Programming (SQP) method with GA. When constructing the Hybrid-GA, there are three problems that should be solved; 1) decision of optimized variables and discrete method, 2) how to use results of local search, and 3) selection for survival method. These problems are discussed and solved in order to effectively combine SQP method with GA. In order to demonstrate the effectiveness of the proposed Hybrid-GA, the TSTO spaceplane optimal design problem, which consists of weight, aerodynamics, propulsion, and flight trajectory analyses, is investigated using the proposed Hybrid-GA, and the optimal results of Hybrid-GA are compared with that of Simple-GA, and SQP methods. Finally, strategy to achieve the TSTO spaceplane is proposed by comparing the optimal results of changing payload weight and maximum wing load factor of booster.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130506323","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 study aims to obtain the optimal flights of a helicopter that reduce ground noise in its landing approach with an optimization technique and to conduct flight tests for confirming the effectiveness of the optimal solutions. Past experiments of JAXA (Japan Aerospace Exploration Agency) shows the noise of the helicopter varies significantly according to its flight conditions, especially depending on the flight path angle. We therefore build a simple noise model of the helicopter, in which the level of the noise generated from a point sound source is a function only of the flight path angle. By using equations of motion for flight in a vertical plane, we define optimal control problems for minimizing noise levels measured at points on the ground surface, and obtain optimal controls for specified initial altitudes, flight constraints, and wind conditions. The obtained optimal flights avoid the flight path angle which generates the large noise and decrease the flight time, which are different from the conventional flight. Finally, we verify the validity of the optimal flight patterns by the flight experiments. The actual flights following the optimal ones also result in the noise reduction, which shows the effectiveness of the optimization.
{"title":"ヘリコプタ着陸進入時における地上騒音低減のための最適飛行 : 最適な高度・速度制御について","authors":"Takeshi Tsuchiya, Hirokazu Ishii, Junichi Uchida, Hiromi Gomi, Naoki Matayoshi, Yoshinori Okuno","doi":"10.2322/JJSASS.54.319","DOIUrl":"https://doi.org/10.2322/JJSASS.54.319","url":null,"abstract":"This study aims to obtain the optimal flights of a helicopter that reduce ground noise in its landing approach with an optimization technique and to conduct flight tests for confirming the effectiveness of the optimal solutions. Past experiments of JAXA (Japan Aerospace Exploration Agency) shows the noise of the helicopter varies significantly according to its flight conditions, especially depending on the flight path angle. We therefore build a simple noise model of the helicopter, in which the level of the noise generated from a point sound source is a function only of the flight path angle. By using equations of motion for flight in a vertical plane, we define optimal control problems for minimizing noise levels measured at points on the ground surface, and obtain optimal controls for specified initial altitudes, flight constraints, and wind conditions. The obtained optimal flights avoid the flight path angle which generates the large noise and decrease the flight time, which are different from the conventional flight. Finally, we verify the validity of the optimal flight patterns by the flight experiments. The actual flights following the optimal ones also result in the noise reduction, which shows the effectiveness of the optimization.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116234357","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":"制御量制約を考慮した高速タンブリング物体の実時間姿勢制御法（第3報）-保存性状態量を利用したフィードバック制御則の導出-","authors":"Y. Tsuda, Shinichi Nakasuka","doi":"10.2322/JJSASS.54.151","DOIUrl":"https://doi.org/10.2322/JJSASS.54.151","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125205361","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}
Experimental and computational studies on supersonic mixing by slotted injection with various injection angle have been conducted. In the experiment flat plate model is installed into supersonic free stream of Mach number of 4 and fully developed turbulent boundary layer is established on the flat plate. The secondary jet is injected through slot nozzle set on the flat plate model in order to simulate SCRAM-jet supersonic mixer. Experiments are conducted by changing injection angle of helium gas in order to observe the effect of injection angle to the supersonic mixing. The flow fields are visualized by the Schulieren method. Also surface pressure distributions and spatial distributions are measured. The same flow fields are simulated by solving tow-dimensional full Navier-Stokes equation of mixture gas of air and helium and calculated results are compared with experiments. Quite good agreement is obtained in wall pressure distributions. And qualitative agreement is obtained in volume fruction distribution. By using the calculated results, the correlations between the mixing rate and the total pressure loss of the flow field are obtained.
{"title":"A Study on the Effect of Injection Angle to Two-Dimensional Supersonic Mixing Flow with Slotted Injection","authors":"Keinosuke Inoue, S. Kawano, S. Aso","doi":"10.2322/JJSASS.54.137","DOIUrl":"https://doi.org/10.2322/JJSASS.54.137","url":null,"abstract":"Experimental and computational studies on supersonic mixing by slotted injection with various injection angle have been conducted. In the experiment flat plate model is installed into supersonic free stream of Mach number of 4 and fully developed turbulent boundary layer is established on the flat plate. The secondary jet is injected through slot nozzle set on the flat plate model in order to simulate SCRAM-jet supersonic mixer. Experiments are conducted by changing injection angle of helium gas in order to observe the effect of injection angle to the supersonic mixing. The flow fields are visualized by the Schulieren method. Also surface pressure distributions and spatial distributions are measured. The same flow fields are simulated by solving tow-dimensional full Navier-Stokes equation of mixture gas of air and helium and calculated results are compared with experiments. Quite good agreement is obtained in wall pressure distributions. And qualitative agreement is obtained in volume fruction distribution. By using the calculated results, the correlations between the mixing rate and the total pressure loss of the flow field are obtained.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121252118","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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