2005 Fiscal Year Final Research Report Summary
Study of Near-Sonic Flows
| Project/Area Number |
14205137
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Aerospace engineering
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKAHASHI Kazuhiro Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (00207854)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUSHIMA Kisa Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (40332514)
OBAYASHI Shigeru Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (80183028)
TAKAYAMA Kazuyoshi Tohoku University, Biomedical Engineering Research Organization, Professor, 先進医工学研究機構, 教授 (40006193)
FUJII Kozo Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Professor, 宇宙科学研究本部, 教授 (50209003)
KIM Hyoung-Jin Tohoku University, Graduate School of Engineering, Research Assistant, 大学院・工学研究科, 助手 (00361121)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Sonic / Shock Wave / Computational Fluid Dynamics / Optimization |
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| Research Abstract |
Numerical and experimental studies of flows at near-sonic speed have been conducted. The following are the major results obtained by this research.
1. The TAS-code, an in-house unstructured-grid based CFD soft, was sophisticated and a practical engineering tool for analyzing and designing transonic airplanes was constructed.
2. An efficient direct optimization code using the adjoint equation was developed. It was applied to optimize the wing-nacelle-pylon integration of a transonic airplane and an important engineering information was obtained.
3. An efficient, multi-disciplinary optimization code for designing a high-performance transonic airplane was developed using the genetic algorithm and the data mining method.
4. A new method to improve the prediction accuracy of the drag by CFD was developed. With this method, an optimization of winglet, which is generally very sensitive to the solution accuracy, becomes possible.
5. A sonic plane at Mach 0.98 was aerodynamically optimized using the TAS-code. The result showed 25% improvement of the lift-to-drag ratio and the important knowledge of a general condition for an efficient sonic plane was obtained.
6. Dynamically unstable tendency of a reentry capsule at transonic speed was numerically analyzed and a prediction method for the dynamic stability of the capsule was proposed.
7. Physics of base flows of a high-speed vehicle was numerically investigated with the LES/RANS hybrid methodology. It was shown that the time-series characteristics at transonic speed was significantly different from other speed regimes.
8. An elevon reversal phenomena at near-sonic speed of a reusable space plane was numerically investigated using the TAS-code and the cause was identified. The method to prevent the elevon reversal was proposed.
9. Various flow phenomena of weak shock waves were experimentally and numerically investigated for the physical understanding.
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