中文摘要：

本研究发展了U—RANS／PDF混合算法研究湍流和化学反应相互作用对燃烧稳定性的影响，采用有限体积和Monte Carlo相结合的方法在非结构网格中求解相容的U—RANS方程和脉动速度-湍流频率-标量的联合PDF方程。本文对钝体火焰驻定器后冷态流场进行了计算，结果表明此混合算法能够捕捉流场中非稳态的漩涡脱落现象。着重研究了湍流频率模型系数的改变对漩涡脱落频率以及拟序结构在动量输运中的作用的影响。

英文摘要：

The study aims to investigate the effects of turbulence-chemistry interaction on combustion instabilities with Probability Density Function （PDF） method. The consistent hybrid Finite Volume/ Monte Carlo algorithm was employed and implemented on triangular unstructured meshes to solve PDF equations for unsteady turbulent flows. This paper focuses on the non-reacting flow behind the triangular-shaped bluff body flame stabilizer. The unsteady vortex shedding phenomena was captured. And the effects of the coefficients in the turbulence frequency model on the shedding frequency and the contribution of coherent and incoherent stresses were examined.