Adaptive refinement/recovery for analysis of wind around structure

For the efficient finite-element wind analysis, using the optimal mesh is one of the most important factors. The optimal mesh can be obtained when the errors of the solution are distributed uniformly over the entire domain. The study presents the development of a transition element for flow analysis, an element that has a variable number of midside nodes and can be effectively used in the adaptive mesh refinement by connecting the locally refined mesh to the existing coarse mesh through a minimum mesh modification. In the dynamic analysis of flow, the optimal mesh should be changed continuously in accordance with the changing error distribution; the proposed refinement/recovery scheme was found to be very effective for this purpose. The modified superconvergent patch recovery for the variable-node element is presented to estimate a posteriori error of the solution for the adaptive mesh refinement. The boundary conditions of the nodes generated by refinement process are different from those used in the ordinary finite-element method, in order to describe the singular point correctly. The numerical examples show that the optimal mesh for the finite-element analysis of flow around the structures can be obtained automatically by the proposed scheme.