| Item type |
紀要論文 / Departmental Bulletin Paper(1) |
| 公開日 |
2015-03-26 |
| タイトル |
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タイトル |
Numerical Analysis of Dynamic Instability at Transonic Speeds |
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言語 |
en |
| 言語 |
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言語 |
eng |
| 資源タイプ |
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資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
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資源タイプ |
departmental bulletin paper |
| 著者 |
寺本, 進
藤井, 孝藏
平木, 講儒
Teramoto, Susumu
Fujii, Kozo
Hiraki, Kouju
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| 著者所属 |
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東京大学 工学部 航空宇宙工学科 |
| 著者所属 |
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宇宙科学研究所 |
| 著者所属 |
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宇宙科学研究所 |
| 著者所属（英） |
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en |
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University of Tokyo, Department of Aeronautics and Astronautics |
| 著者所属（英） |
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en |
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Institute of Space and Astronautical Science (ISAS) |
| 著者所属（英） |
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en |
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Institute of Space and Astronautical Science (ISAS) |
| 出版者 |
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出版者 |
宇宙科学研究所 |
| 出版者（英） |
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出版者 |
Institute of Space and Astronautical Science |
| 書誌情報 |
en : The Institute of Space and Astronautical Science report. S.P. : Aerodynamics, Thermophysics, Thermal Protection, Flight System Analysis and Design of Asteroid Sample Return Capsule
巻 17,
p. 275-300,
発行日 2003-03
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| 抄録（英） |
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内容記述タイプ |
Other |
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内容記述 |
A flat capsule with blunt nose like Muses-C reentry capsule tends to be dynamically unstable at transonic speeds. This instability phenomena has been studied experimentally since 1960's, but its mechanism is not well understood. The flowfield around the reentry capsule is numerically simulated and discussed to reveal the mechanism of the dynamic instability. A new post-processing technique that uses frequency filters, are applied to detect the flow structure out of complicated flowfield. The results showed that the base pressure of the capsule produces pitch-down moment for the positive pitch angle, and the oscillation of the base pressure is delayed from the pitch angle when the capsule oscillates in pitch. The delay causes the hysteresis in the aerodynamic pitching moment, and the hysteresis makes the capsule dynamically unstable. The base pressure and the wake at the neck point (the foot of the recompression shock wave) oscillate with the same delay time. When the neck point moves upward, the pressure at the upper part of the base becomes higher and the base pressure produces pitch-down moment. Two oscillations coincides each other, and therefore the base pressure is correlated to the flowfield near the neck point. There is strong reverse flow behind the capsule, and the impingement of the reverse flow against the base determines the base pressure distribution. The behavior of the reverse flow is governed by the vortex structure behind the capsule. The vortex is composed of the ring vortex and the pair of longitudinal vortices, and the interaction between the longitudinal vortices and the flowfield near the neck point defines the base pressure distribution. The base pressure does not change until the disturbance of the longitudinal vortices caused by the pitching motion of the capsule reaches the neck point, and the time lag is the cause of the phase delay of the base pressure. Both the base pressure distribution and the delay of the base pressure are governed by the pair of longitudinal vortices, and therefore the dynamic stability of the capsule is closely related to the formation of the pair of longitudinal vortices. |
| ISSN |
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収録物識別子タイプ |
ISSN |
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収録物識別子 |
0288-433X |
| 書誌レコードID |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA10455137 |
| 資料番号 |
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内容記述タイプ |
Other |
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内容記述 |
資料番号: SA0200030000 |
SA0200030.pdf (6.5 MB)
