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Liutex similarity in turbulent boundary layer 被引量:9
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作者 Wen-qian Xu Yi-qian Wang +3 位作者 Yi-sheng Gao Jian-ming Liu Hua-shu Dou Chaoqun Liu 《Journal of Hydrodynamics》 SCIE EI CSCD 2019年第6期1259-1262,共4页
Kolmogorov's 1941 theory(K41)of similarity hypotheses and the-5/3 law for energy spectrum are considered as the most important theoretical achievement in turbulence research and the success of the modem turbulence... Kolmogorov's 1941 theory(K41)of similarity hypotheses and the-5/3 law for energy spectrum are considered as the most important theoretical achievement in turbulence research and the success of the modem turbulence theory.The assumptions of sufficient high Reynolds number and isotropy of turbulence that K41 based upon,however,cannot generally be met in practice,and thus discrepancy is often observed between the f law and direct numerical simulation(DNS)results of boundary layers in wall bounded turbulence,especially for moderate to low Reynolds number flows.Liutex vector is a recently defined new physical quantity which is extracted from turbulent flow to represent the rigid rotation part of fluid motion.Actually,Liutex is free from viscous dissipation and thus independent of Reynolds number,relaxing the very high Reynold number assumption of K41.Liutex similarity has been solidly demonstrated by DNS for a moderate Reynolds number turbulent boundary layer(Reθ≈1000),both the frequency and wavenumber spectrum of Liutex accurately matches the-5/3 law,which is obviously much better than the turbulence energy spectrum,while vorticity and other popular vortex identification methods,Q criterion for example,do not possess such a distinguished feature due to stretching and shearing contamination. 展开更多
关键词 -5/3 law Liutex similarity K41 turbulent boundary layer moderate and low Reynolds number
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AN ADAPTIVE CONTROL STRATEGY FOR PROPER MESH DISTRI-BUTION IN LARGE EDDY SIMULATION 被引量:5
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作者 ZHANG Bin WANG Tong +1 位作者 GU Chuan-gang DAI Zheng-yuan 《Journal of Hydrodynamics》 SCIE EI CSCD 2010年第6期865-870,共6页
The Filtering Grid Scale (FGS) of sub-grid scale models does not match with the theoretical Proper FGS (PFGS) because of the improper mesh. Therefore, proper Large Eddy Simulation (LES) Mesh is very decisive for... The Filtering Grid Scale (FGS) of sub-grid scale models does not match with the theoretical Proper FGS (PFGS) because of the improper mesh. Therefore, proper Large Eddy Simulation (LES) Mesh is very decisive for better results and more economical cost. In this work, the purpose is to provide an adaptive control strategy for proper LES mesh with turbulence theory and CFD methods. A new expression of PFGS is proposed on the basis of -5/3 law of inertial sub-range and the proper mesh of LES can be built directly from the adjustment of RANS mesh. A benchmark of the backward facing step flow at Re = 5147 is provided for application and verification. There are three kinds of mesh sizes, including the RANS mesh, LAM (LES of adaptive-control mesh), LFM (LES of fine mesh), employed here. The grid number of LAM is smaller than those of LFM evidently, and the results of LAM are in a good agreement with those of DNS and experiments. It is revealed that the results of LAM are very close to those of LFM. The conclusions provide positive evidences for the novel strategy. 展开更多
关键词 Large Eddy Simulation (LES) Proper Filtering Grid Scale (PFGS) TURBULENCE -5/3 law adaptive control
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