线性分层流中圆柱绕流数值模拟方法研究

Numerical study of linearly stratified flow past a cylinder based on a multiphase mixture model

为达到研究连续分层流中航行潜体尾迹探测之目的,探讨了线性分层流中基于多相流混合模型的圆柱绕流数值模拟方法。首次采用LES方法数值模拟了高傅汝德数下分层流动,成功模拟出试验条件下对应傅汝德数下的尾迹特征;用RANS方法实现了对低傅汝德数低雷诺数下分层流动流场的定量描述;通过对高雷诺数不同湍流模型下的流动展开讨论,发现采用不受各向同性假设限制的RSM模型进行分层湍流数值模拟是合理的,且对近壁面的处理要采用壁面函数的方法。基于多相流混合模型建立了傅汝德数从低到高,粘性模型从层流至湍流各个取值段模拟分层流动的数值方法。

To test the wake of a submarine during navigation in a continuous stratified fluid,in this paper,we numerically investigate linearly stratified flow past a cylinder based on a multiphase mixture model. First,we used large eddy simulation（ LES） to simulate stratified flow at a high Froude number,and found the characteristics of the wake to correspond well with experimental results. Next,we used a Reynolds-averaged Navier-Stokes（ RANS）model to simulate stratified flow at low Froude and low Reynolds numbers,and for the first time achieved quantitative descriptions of the flow field. By numerically investigating the flow of different turbulence models with a high Reynolds number,we found the Reynold＇s stress model（ RSM） that is not restricted by the isotropic hypothesis to be the most reasonable model for simulating stratified turbulent flow. Also,the wall function should be used for circumstances concerning near-wall treatment. Based on the multiphase mixture model,we establish a numerical method in the Froude range from low to high and a viscous model ranging from laminar to turbulent.