本文探討非對稱旋轉物體在高雷諾數下流場，及旋轉掉落之流場。採用商用計算流體力學軟體Ansys Fluent進行模擬計算，數值方程使用SST-k-omega紊流模型進行計算。本研究皆使用Ansys Fluent Meshing 劃分網格，採用六面體與多面體的混合型(Hybrid)非結構網格。在高雷諾數側風下模擬不同的初始旋轉速度，受到固定速度側風的影響，觀察在旋轉比(spin ratio)0、1和2三種不同轉速的流場分布，並監測其擺正後不同旋轉比隨時間變化的阻力係數、大地座標下的受力和渦流分離等現象，進而觀察渦流分離的頻率和史特豪數(Strouhal number)對姿態產生的關聯。暫態掉落模擬在自由掉落以及終端速度時多種側風速度的姿態變化，採用重疊網格的方法進行計算，計算每個時間步的受力、速度、轉速、掉落軌跡和尤拉角，找出影響受力週期性的重要參數。
本論文首先進行軟體驗證，與高雷諾數流經圓柱和其他動態掉落的的相關文獻比對，以此增加模擬數據可信度。探討六自由度的運動方式和計算方法是非常重要的，尤其在動態網格的設定，重疊網格的劃分與背景網格不能相差太多，設定上的差異可能導致結果誤差變大，藉由本研究提供給致力於研究非對稱旋轉體落體此領域一些建議。在同樣雷諾數為45182的流場中，三種旋轉比，r=0、1、2，對非對稱本體或流場產生不同的影響，在旋轉比為0和1時，後方流場皆產生渦流分離的現象，到旋轉比為2時，因轉速過快而破壞了渦流分離的結構。受力的週期性又是由後方的渦流分離主導的，與旋轉的速度無直接的關聯。從旋轉掉落結果分析，渦流分離對受力的影響不大，觀察相關的流場和姿態的改變也可以合理認為週期性主因為旋轉時的姿態所產生的。無側風本身就會讓轉速減慢，側風速度的增加反而會讓轉速減慢的趨勢更明顯。

The analysis of the flow field of an asymmetric rotating body with high Reynolds number and the other analysis of the transient flow field of a rotating body freely falling affected by the crosswind. The commercial computational fluid dynamics software Ansys Fluent was used for these simulations. The governing equations are the compressible Navier-Stokes equations coupled with the SST-k-omega turbulence model. In this dissertation, Ansys Fluent Meshing was used to generate the mesh, which was a hybrid unstructured mesh of hexahedron and polyhedron. Simulate different initial rotation speeds under different speed crosswinds. Observe the flow field at three different spin ratio 0, 1, and 2. Then monitor the time-varying drag coefficient, the global coordinate force, and vortex shedding, etc., and observe the relationship between the frequency and Strouhal number of vortex shedding and the attitude of body. First, this dissertation conducted the verification of software, and compared it with the related literature about flow past the cylinder under higher Reynolds number and other dynamic falling, so as to increase the credibility of the simulation data. The calculations were carried out by the method of overset grids. The force, velocity, speed, rotation speed, falling trajectory and Euler angle of each time step were calculated. Eventually, find out the important parameters that affect the periodicity of the force.

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