Abstract
當高雷諾數流場流經一鈍體時，其後通常會產生一種非穩態、週期性變化的大型渦流結構－渦流逸放。這是一種源自於流場的不穩定性而在分離點之後，剪力層之內劇烈變化的結構。本文以Power-Law差分法、SIMPLE及PISO演算法、RSM紊流模式配合壁函數以模擬二維管道內紊流場(Re=13,600 )流經方形鈍體後的尾流。本文從管道正中間開始，漸次把鈍體往壁面移動以期找出發生渦流逸放的臨界間隙，同時並探討不同鈍體位置的流場變化及所承受的氣動負載。本文為了測試數值方法的可行性，先將其運用於背向階梯流場；藉著模擬背向階梯流場例子的成功，以繼續從事紊流場渦流逸放的研究。Vortex-shedding is a coherent structure.It is natural ofperiodic unsteady and often induced by flow past bluff body.Inthis study we use Power-Law scheme,SIMPLE and PISO algorithm,RSM turbulence model with wall function to simulate 2-Dturbulent channel flow( Re=13,600)past square bluff body.Numerical solutions are shown by instantaneous streamline,averaged streamline,power spectra, instantaneous values ofmonitor point and aerodynamics loading. At first,We practiceour numerical method to flow over a backward -facing step tocheck it's justify.