抄録
Formal explicit filtering defined by the convolution integral over a flow region has been applied to derivefundamental equations of Large Eddy Simulation (LES) for turbulent flows over complex boundaries that are common in natural environment, in which details of the flow and the boundary geometry cannot be resolved in full and modelingis needed. Formal filtering in finite and complex domain allows filtering of the flow and boundary at the sametime and indicates that extra stress-like terms appear in the equations. DNS data obtained in a flow over wavy boundary are analyzed to examine the distributions of these terms and a similarity in the filtered flow that may be useful in formulating boundary conditions in a simulation calculation that does not resolve the details of the boundary. It is found that the filtering brings out the effects of the roughness of the boundary as additional stresses, most of which come from the contribution of the pressure forces on the original boundary.
