Simulation of vortex shedding behind a bluff body flame stabilizer using a hybrid U-RANS/PDF method

作     者：Min-Ming Zhu Ping-Hui Zhao Hai-Wen Ge Yi-Liang Chen 

作者机构：Department of Thermal Science and Energy EngineeringUniversity of Science and Technology of China230027 HefeiChina Engine Research CenterUniversity of Wisconsin-Madison1500 Engineering DriveMadisonWI 53706USA 

出 版 物：《Acta Mechanica Sinica》 (力学学报（英文版）)

年 卷 期：2012年第28卷第2期

页      面：348-358页

核心收录：

学科分类：080702[工学-热能工程] 080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China (50936005) the Fundamental Research Fundsfor the Central Universities (WK2090130008,WK2090130011) 

主　　题：Vortex shedding PDF method Unsteady RANS Finite volume. Bluff bodies 

摘      要：The present study aims at the investigation of the effects of turbulence-chemistry interaction on combus- tion instabilities using a probability density function （PDF） method. The instantaneous quantities in the flow field were decomposed into the Favre-averaged variables and the stochastic fluctuations, which were calculated by unsteady Reynolds averaged Navier-Stokes （U-RANS） equations and the PDF model, respectively. A joint fluctuating velocity- frequency-composition PDF was used. The governing equa- tions are solved by a consistent hybrid finite volume/Monte- Carlo algorithm on triangular unstructured meshes. A non- reacting flow behind a triangular-shaped bluff body flame stabilizer in a rectilinear combustor was simulated by the present method. The results demonstrate the capability of the present method to capture the large-scale coherent struc- tures. The triple decomposition was performed, by divid- ing the coherent Favre-averaged velocity into time-averaged value and periodical coherent part, to analyze the coherent and incoherent contributions to Reynolds stresses. A sim- ple modification to the coefficients in the turbulent frequency model will help to improve the simulation results. Unsteady flow fields were depicted by streamlines and vorticity con- tours. Moreover, the association between turbulence produc- tion and vorticity saddle points is illustrated.