Three-dimensional numerical simulations of fluid dynamics problems on grids with nonconforming interfaces

The paper describes a numerical method, which considers specific CFD (computational fluid dynamics) aspects of viscous incompressible flow simulations in the vicinity of interfaces between nonconforming grid fragments. An example implementation of the method is presented for the case of the finite-volume approximation of the Navier-Stokes equations. The method is based on the GGI (General Grid Interface) principle, which does not require initial grid modification and involves conservative flux interpolation. This method enables simulations of viscous incompressible flow simulations on grid models of complex-geometry structures composed of several independently constructed grid fragments, which have nonconforming grids at adjacent boundaries and can be joined together through nonconforming interfaces. The paper reports simulation results for turbulent flow in a circular tube with an abrupt reduction in diameter on a grid model composed of nonconforming unstructured grid fragments. The effect of the nonconforming interface on the accuracy of solution and the rate of convergence of iterations is demonstrated.