横流中射流及其温度标量输运大涡模拟

将动力拟序涡黏性亚格子应力模型拓展到温度标量亚格子模型中,数值模拟了横流条件下有、无温度标量场作用的射流,得到的横流条件下浮力射流的温度和速度分布与Anwar的试验值吻合一致。在此基础上,分析了有、无温度标量场作用下射流回流区域大小和射流轨迹线特性,对比分析了回流区域内涡心和分离点处湍动能和耗散率、拟涡能以及边界层处拟序结构等湍流特性。计算结果表明:温度场的作用使射流的回流区域增大,射流速度轨迹线高度增加,回流区域内湍流的湍动能增加,边界处拟序结构的周期性不如无温度场时明显。

Large eddy simulation of jets with and without temperature scalar in a current

The jet in cross flow was simulated using a dynamic coherence eddy subgrid stress model,which was expanded into a subgrid heat flux model,under the action of temperature field.The results show that the temperature and velocity distributions of a buoyant jet in cross flow obtained from the numerical simulation are in good agreement with Anwar's experimental data.The characteristics of backflow zones and the trajectory lines of the jets were investigated with and without temperature field.The turbulence kinetic energy and the turbulence eddy dissipation in the vortex core were compared with those of the separation point of backflow zones.The calculated results show that the areas of the backflow zones,the jet trajectory line height,and the turbulence kinetic energy increase under the action of temperature field.The period of the coherent structures near the boundary layer becomes unobvious under the action of temperature field.