Automated Grid Independence Via Unstructured Adaptive Refinement

Abstract

Grid independence is frequently an overlooked item in CFD analyses. Often an attempt is made to perform due diligence towards this end, but time and resource constraints prevent this from becoming reality. Results obtained from grid dependent solutions may prove to be costly, in that design decisions can be made using potentially faulty information. Therefore, grid independence should be viewed as an extremely important element of any CFD study. An Automated system for Grid Independence (AGI) for 2D unstructured wall function grids is presented here. In this system, grid independence is achieved via successive levels of grid refinement. This is accomplished by utilizing grid adaptation based upon solution variables in an automated fashion. Three cases are examined, the backward facing step, flow over an asymmetric transonic airfoil and hydrogen combustion in a channel. Grid independent solutions are obtained for all three cases. Results for each case compare well with experimental and/or other numerical predictions.