基于温度异重流模型的连续分层流数值模拟方法研究

文章基于温度异重流模型,通过指定流场中温度的分布及密度与温度的函数关系实现密度的连续分层,并假设流场中的热传导在数值过程中可以忽略不计以确保密度分层的稳定。分别采用RANS方法和LES方法对低傅汝德数和高傅汝德数情况下的圆柱绕流进行数值模拟,其尾流场中的lee波、葫芦状流线以及高傅汝德数情况下的波包与实验值相符,低傅汝德数情况下圆柱上下游速度剖面曲线的最小值与实验值仅存在2%的误差,且其分布规律相同。通过改变流体的导热系数,探讨了Peclet数对该方法收敛稳定性的影响,得到了收敛的数值条件。

Research on the numerical simulation methods of continuously stratified flows based on thermal density current model

Based on thermal density current model, the continuous stratification of density is achieved by specifying the distribution of temperature and regarding density as a function of temperature. It is assumed that the heat conduction is negligible to ensure the stability of density stratification. The RANS method and LES method are used respectively to simulate the flows past a cylinder at low Froude numbers and high Froude numbers. The lee waves, gourd-shaped streamlines and wave packets are consistent with the exper-imental results. For the minimum values of velocity profile curves, there are only 2%errors between the cal-culated and experimental values, and the curve shapes are the same. The influences of Peclet numbers on the stability of this method are discussed by changing the heat conductivity coefficient of fluid. Finally, the numerical conditions of convergence are obtained.