基于共振三波的大涡模拟壁面模型

大涡模拟的一个重要发展方向是处理工程流动问题,但高雷诺数下近壁湍流边界层对计算网格的过高要求成为制约其应用的主要瓶颈;要减少计算量,构建合理且能够正确反映近壁湍流动力学特性的壁面模型是一条有效途径.在此背景下,构造了一种计算中便于实现的基于共振三波的壁面模型.通过对充分发展槽道湍流算例的研究,完成了对该模型构造方法、方案的论证和验证计算.结果表明使用壁面模型后,在减少计算量的同时,定性和定量的结果均较为合理,能够得到重要的瞬态特征结构和正确的一阶、二阶统计量,从而部分验证了该方法的有效性.

Wall model for large-eddy simulation based on resonant triad waves

Large-eddy simulations (LES)were developed to deal with engineering problems in recent decades. The cost of LES of wall-bounded flows depended strongly on the Reynolds number. Wall models to bypass the wall layer and contain adequate near-wall region kinetics were required to perform high-Reynolds-number LES at a reasonable cost. For this purpose, the wall model based on resonant triads was constructed, which was easier to perform in numerical simulations. The methodologies and key strategies of the model were described and the results of full-developed channel flows show that typical structures of the main flow are reasonable compared with well-resolved examples (without wall-models) and significant first- and second-order statistics are consistent well with well-resolved results.