大雷诺数下方柱绕流PIV试验及数值模拟

PIV Experiment and Simulation of Flow Around a Square Cylinder at High Reynolds Numbers

基于风洞试验利用粒子图像测速技术(PIV)研究了大雷诺数(Re=3.42×10~4)下方柱绕流流场,并应用本征正交分解(POD)法分解PIV瞬态速度场,获得了方柱尾流的低阶模态和重构流场结果,研究方柱绕流的流动机理.采用γ-Re_θ和k-ωSST两种湍流模型研究了大雷诺数下方柱尾流的速度分布以及湍动能变化。风洞PIV试验可准确的观测方柱尾流脉动流场,基于POD方法得到的前6阶模态占总能量的78.7%,前6阶模态即可较准确重构流场并捕获流场的主要特征。通过对比,γ-Re_θ模型是较优的湍流模型,可较好地得到尾流的湍动能及其变化规律。

The flow around the square cylinder at high Reynolds number （Re=3.42×10^4） has been studied by particle image velocimetry technology （PIV） based on the wind tunnel experiment. The proper orthogonal decomposition （POD） was applied to PIV data post-processing to obtain the low modes and reconstruction of wakes to study the flow mechanism around the square cylinder. And the velocity profile and turbulence of wake were simulated by γ-Reθ transition and κ-ω SST turbulence model. That shows the PIV capture the characteristic of flow field accurately. The first six modes obtained by POD accounts for 78.7% of the total energy, and the first six modes reconstitute exactly the flow field as well as demonstrate main characteristics. According to the comparison, it can be concluded that the turbulent energy of wakes can be simulated well by means of the γ-Reθ transition model.