Oscillationless Explicit Method on Overset Grid for Advective Equation

Abstract

Characteristics of numerical errors using the overset grid method are investigated. The overset grid method has some problems with the interpolation of data between each mesh. In the case of the computing advective equation, a traveling wave passing through an interface of overlapping meshes causes numerical oscillations. The oscillations near the interface destroy the solution, and cause overflow. In order to investigate the causes of the numerical errors on the overset grid, we apply wave analysis on each component mesh. We show that phase differences between component meshes cause the numerical errors and that the accuracy of the phase velocity is quite important to compute the advective equation with less numerical errors on the overset grid. We suggest that calculations using accurate phase velocity will reduce numerical errors. We show that CIP scheme is one of the most useful schemes to represent wave propagation with high accuracy and without oscillation on the overset grid.