Large eddy simulation of turbulent flows around bluff bodies in overlaid grid systems

For accurate large eddy simulation (LES) of complex turbulent flows around bluff bodies with various shapes, we have investigated the effects of the upwind scheme on wake structures and the problems in overset grid systems, which require interpolation of physical values between sub-domains. For the former LES of turbulent flows around a circular cylinder at Reynolds number (Re)=10,000 was carried out with or without using a third-order upwind scheme. As distorted wake structures can be observed when using an upwind scheme, it is desirable to perform LES without using an upwind scheme. For the latter, we propose an overset grid method under LES without using an upwind scheme, because inaccurate conservation of physical values in the region connecting sub-domains causes numerical instability and inaccurate solution. The proposed method improves the standard deviation of pressure distributions around a circular cylinder at Re=10,000.