中文摘要：

采用大涡模拟的方法对两无穷大平板间受热形成的羽流进行了数值模拟．控制方程为三维不可压N-S方程组，数值格式采用了高精度的伪谱方法，亚格子模型则采用了TNS模型、首先对槽道流进行了模拟，通过比较大涡模拟和直接数值模拟的结果对此方法进行了验证．随后数值模拟了热力羽流的输运过程，分析讨论了相关的温度场和速度场，并比较了不同Rayleigh数对流动特性的影响．结果表明当Rayleigh数比较大时，热浮力对流动的影响比较大，形成了比较复杂的流动结构．

英文摘要：

Thermal plume formed by the heat between two parallel infinite walls was studied with large eddy simulation （LES）. The filtered three dimensional incompressible Navier-Stokes equations were numerically solved in high order pseudospectral method. The sub-grid stress was modeled with the TNS model. The numerical method was first applied to channel flow and verified by comparing the results of LES and direct numerical simulation （DNS）. Then, the transportation procedure of thermal plume formed by the heat source was simulated. The typical flow characters and temperature fields were investigated. The effects of different Rayleigh numbers on the thermal plume have also been compared. It has been found that, when Rayleigh number is higher, the effect of the buoyancy force is also larger, and the complicated flow structure is formed.