| Project/Area Number |
04452110
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Aerospace engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
YOSHIZAWA Yoshimasa Univ.of Tsukuba, Inst.Eng.Mech.Prof., 構造工学系, 教授 (30029392)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANE Takashi MITI,Mech.Eng.lab.Chief Res.Officer, 機械技術研究所, 主任研究官
MURAKAMI Masahide Univ.of Tsukuba, Inst.Eng.Mech.Prof., 構造工学系, 教授 (40111588)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1992: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Helicopter Aerodynamics / Helicopter Rotor / Helicopter Wake / Pressure Distribution on Rotor / TVD Scheme / Runge-Kutta method / ヘリコプターローター / 非定常三次元流 / 4次精度ルンゲクッタ法 / 回転翼 / ヘリコプター / 高次精度時間積分 / 翼面上の衝撃波 |
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| Research Abstract |
The computational method of flowfield of rotating helicopter rotors has been established. After examining and compairing existing computational methods on unsteady compressible flows, a combination of the fourth-order accurate Runge-Kutta method in time and the second-order accurate upwind TVD scheme including a flux limiter is the best choice among many techniques from the viewpoints of accurate description of the flow field and reasonable computing time. With this method it is still very difficult to simulate flows around real helicopter rotors, since unsteady three-dimensional characteristics of rotors and interactions between flow around rotors and wakes from rotors are essential to describe aerodynamics of helicopter rotors.
Though the present method is expected to be one of the most powerful methods to analyze the flow around helicopter rotors, more advanced supercomputers are required to give data for engineering purposes and design processes. From these reasons the present calculations are limited to rather small two rotors model. In spite of these restrictions some essential features of helicopter rotor aerodynamics are clearly shown, that is, changes of flow patterns by rotation and interaction with rotor wake. In a forward flight condition estimation of rotor performance is possible after ca.2 rotations. On the other hand, several rotations, at least 6 or more, will be required to obtain accurate results since spiral wake remains downwards. In forward flight conditions angle of attack must be changed to balance the lift in advancing and receding rotor side, this computational procedure can easily be included by using moving computational grid, which means 20% increase in calculating time.
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