Direct numerical simulation of bluff body flows using non-staggered grids

The present authors pointed out in the previous paper [1] that the implicit SMAC scheme is quite efficient and non-staggered grid arrangement can decr ease the computational effort and save the storage memory which is very imp ortant to the direct numerical simulation (DNS) of complicated 3-D flow fie lds. But using non-staggered grid arrangement, the pressure field oscillati on (PFO) ordinarily occurs and also, the pressure on the solid walls includ ing sharp corners need to be prescribed directly as the pressure boundary c onditions. In this paper, a new interpolation method, which is a modification to Cheng and Armfield's interpolation formulation, is presented in order to complet ely prevent PFO from occurring. Moreover, a more accurate specification met hod of wall pressures and special treatment of pressures at sharp corners a re proposed. To test the new methods proposed, the DNS of flow past a squar e cylinder and flows over backward-facing steps, which are typical of the h ow fields with sharp corners, is made using the implicit SMAC scheme combin ed with these methods. The calculated results are compared with the previou s experimental and numerical data and show good agreement with them.