A node-centered pressure-based method for all speed flows on unstructured grids

Abstract

This article proposes a node-centered pressure-based method for predicting flows at all speeds on unstructured grids. The compressible version of the SIMPLE algorithm is extended to unstructured grids. For memory and computing time efficiency of arbitrary cell topologies, a node-centered scheme with edge-based data structure is applied to the segregated unstructured-grid algorithm. Convection terms are discretized using the second-order scheme with a deferred-correction approach. Diffusion-term discretization is based on the structured-grid analogy, which can be easily adapted to hybrid unstructured grid solvers. By using the proposed approach, three test eases in the continuum regime are computed. The demonstration of this method is extended to a slip flow problem that has low Reynolds number and compressibility effect. Predictions are compared to other results, which show that the proposed method can improve efficiency in memory usage and computing time without losing any accuracy even in mixed-element grids.