ASSESSMENT OF GRID INTERFACE TREATMENTS FOR MULTIBLOCK INCOMPRESSIBLEVISCOUS-FLOW COMPUTATION

In the multi-block computation of the Navier-Stokes equations, the int erface treatment is a key issue. In the present work, we investigate t his issue in the context of a pressure-based method using a non-orthog onal grid. For the momentum equations, a straightforward bilinear inte rpolation seems satisfactory as the interface treatment; on the other hand, because the pressure field depends on the satisfaction of the ma ss continuity equation, a conservative interface treatment has been fo und necessary for the pressure-correction equation. Two alternative in terface treatments for the pressure-correction equation, one employing the Neumann boundary condition in both grid blocks, based on explicit local, cell-by-cell mass flux conservation, and the other utilizing N eumann-Dirichlet boundary conditions, allowing the interface condition in one block to be derived by interpolating the pressure field from t he adjacent block, are assessed in the present work. To evaluate these interface schemes, the laminar flow inside a lid-driven cavity flow, and the turbulent flow around cascades of multiple airfoils have been investigated. For the case tested, both interface treatments give comp arable accuracy. The finding that more than one type of interface trea tment can work well allows one to devise a flexible multi-block strate gy for complex flow computations. Copyright (C) 1996 Elsevier Science Ltd.