Fully implicit method for coupling multiblock meshes with nonmatching interface grids

Abstract

A newly developed efficient and fully implicit method for multiblock mesh coupling that preserves the convergence characteristics of single-block meshing is presented. The technique is developed in the context of an unstructured pressure-based collocated finite-volume method, is applicable to both segregated and coupled flow solvers, and is ideal for code parallelization. The discretization at interfaces is performed in a separate step to stitch the regions sub-matrices into a global matrix. By solving the global matrix, the solution achieved to the multiregion problem is exactly the one that would result from a single-mesh discretization. The method is tested by solving three laminar flow problems. Solutions are obtained by meshing the domain as one block or by subdividing it into a number of blocks with non-matching grids at interfaces. Results show the very tight coupling at interfaces with a convergence rate that is independent of the number of blocks used. © 2017 Taylor & Francis.