| Summary: | 碩士 === 中華大學 === 機械與航太工程研究所 === 94 === Several turbulent models were used for unsteady turbulent flows around moving solid bodies. At a steady low angle attack without separation on the airfoil, the κ-ε models give a better results compared to κ-ω models. At a steady mild angle attack with light stall on the airfoil, the high Reynolds number κ-ω model and Jones-Launder κ-ε model give a closer pressure coefficient compared to other turbulent models. At a high angle attack with deep stall on the airfoil, only the high Reynolds number κ-ω model provides a better result. A pseudo time Runge-Kutta time marching scheme was used to solve the flow around an oscillating airfoil. The Launder-Sharma κ-ε turbulent model predicts better than the other models in the lift and drag hysteresis loops for light-stall cases. For the moment coefficient hysteresis loop, the high Reynolds number κ-ω model provides a better prediction. There exist large difference between the computations and experiment for deep stall cases. Overall, the high Reynolds number κ-ω model provide better results than the other models. This can be attributed to the better behavior of separation calculation.
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