Efficient parallel communication schemes for computational fluid dynamics codes

A scheme for improving the efficiency of communications for the parallel computation of Euler equations is presented. The NPARC (National PARC) code is employed as an example for analyzing the flow through a supersonic inlet. The how-held is divided into subregions called blocks. The parallel computation of the problem normally requires communication between each block after each time step of an explicit Runge-Kutta integration scheme. In the developed procedure, the boundary conditions are frozen for k = 10-20 time steps, and blocks are integrated in time without communication with each other during this period. When the boundary conditions are updated, an oscillatory error is introduced into the solution with a fundamental period of 4k time steps, which is then filtered in time, As a result, the communication cost of parallel computing is significantly reduced, Examples for steady and unsteady hows are presented to demonstrate the applicability of the developed procedure.