摘要
合成湍流作为一种能够有效抑制"灰区"问题的手段,在RANS-LES混合模拟中得到了广泛应用。由于空腔流动中存在主导的自持振荡机制,添加合成湍流对其RANS-LES混合模拟结果的影响目前还不明确。本文详细比较了合成湍流对马赫数0.6空腔流动的分区和非分区混合模拟带来的影响:对于剪切层,合成湍流显著增加了旋涡结构的三维特性和湍动能的大小;对于腔内的流动,添加合成湍流增大了后壁附近环流区的尺寸,进而降低了靠近后壁区域的剪切层动量厚度和平均压力分布,模拟结果更接近实验数据。合成湍流的使用会诱导产生更高频的模态,但是对Rossiter模态基本没有影响。通过对不同位置展向波数谱的比较,发现合成湍流对模拟结果的影响是通过改变腔内流动的三维机制而产生的。对比研究说明,如果主要关注流动的三维特性(如展向失稳模态),则来流边界层中的合成湍流脉动将对空腔流动的RANS-LES混合模拟结果有重要影响。
As an effective method for mitigating the"grey area"problem,the synthetic turbulence has been extensively used in the hybrid RANS-LES simulations.Due to the existence of the dominated self-sustained oscillation mechanism of cavity flows,the influences of the synthetic turbulence on the results of hybrid simulations are still not clear.Such influences on the zonal and non-zonal hybrid simulations of the cavity flow of Ma=0.6 are compared in detail:For the shear layer,the synthetic turbulence increases the three-dimensionality of the vortical structures and the turbulent kinetic energy.For the flow inside the cavity,the size of recirculation zone near the aft-wall become larger when the synthetic turbulence(ST)is added.Moreover,the momentum thickness of the shear layer and the mean pressure are reduced in the same region.The mean pressure with synthetic turbulence show good agreement with the experiment measurement.The employment of the ST would induce an additional mode with higher frequency,but has no effects on the Rossiter’s modes.Through comparing the spanwise wavenumber spectra at different locations,it is found that the influences of the synthetic turbulence on the simulation results are produced by altering the three-dimensional flow mechanism.This study suggests that the synthetic turbulent fluctuations in the inflow boundary layer would significantly influence the results of the HRLM of the cavity flow,if the three-dimensionality(such as the spanwise instability)is of great concern.
作者
郭启龙
李辰
刘朋欣
孙东
张涵信
GUO Qilong;LI Chen;LIU Pengxin;SUN Dong;ZHANG Hanxin(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center,Mianyang 621000,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;National Laboratory of Computational Fluid Dynamics,Beihang University,Beijing 100191,China)
出处
《空气动力学学报》
CSCD
北大核心
2020年第5期980-988,I0004,共10页
Acta Aerodynamica Sinica
基金
国家数值风洞工程。
