摘要
In this work we extend the method of the constrained large-eddy simulation(CLES)to simulate the tur-bulent flow over inhomogeneous rough walls.In the original concept of CLES,the subgrid-scale(SGS)stress is constrained so that the mean part and the fluctuation part of the SGS stress can be modelled separately to improve the accuracy of the simulation result.Here in the simulation of the rough-wall flows,we propose to interpret the extra stress terms in the CLES formulation as the roughness-induced stress so that the roughness inhomogeneity can be incorporated by modifying the formulation of the constrained SGS stress.This is examined with the simulations of the channel flow with the spanwise alternating high/low roughness strips.Then the CLES method is employed to investigate the temporal response of the turbulence to the change of the wall condition from rough to smooth.We demonstrate that the temporal development of the internal boundary layer is just similar to that in a spatial rough-to-smooth transition process,and the spanwise roughness inhomogeneity has little impact on the transition process.
基金
supported by the National Natural Science Foundation of China (Grants 11988102, 91752201, and 11822208)
the Department of Science and Technology of Guangdong Province (Grant 2019B21203001)
Key Special Project for Introduced Tal ents Team of Southern Marine Science and Engineering Guang dong Laboratory (Guangzhou) (Grant GML2019ZD0103)
Shenzhen Science & Technology Program (Grant KQTD2018 0411143441009)
supported by Center for Computational Science and Engineering of Southern University of Science and Technology
the support from Centers for Mechanical Engineering Research and Education at MIT and SUSTech
