大涡模拟进口合成湍流方法

进口瞬时湍流脉动条件直接影响大涡模拟的精度。对比研究了更适合工程应用的合成涡和合成谱方法,并通过考虑进口速度时间相关和随机数的概率密度分布,对合成谱方法进行改进。对零压力梯度平板湍流模拟结果的对比表明:不同湍流合成方法得到的合成湍流均存在发展为真实湍流的过渡过程;考虑进口湍流脉动的时间相关有助于合成湍流更快地发展为真实湍流,需要的流向距离更短;合成谱方法采用正态分布系数优于均匀分布,改进的合成谱方法优于常规合成谱方法。

Inlet synthetic turbulent methods for large eddy simulation

Transient turbulent inlet condition is important for large eddy simulation. Synthetic vortex method and synthetic spectral method were compared with improved synthetic spectral method considering inlet time correlation and probability for random coefficients. Simulation of zero pressure gradient flat plate turbulent flow showed that the development from synthetic to real turbulences existed under all synthetic turbulent conditions. Time correlation was in favor of the process so shorter streamwise distance was needed. Normal probability distribution was better than uniform distribution for synthetic spectral method.