Optimized Locally Exact Numerical Scheme Based on Finite Variable Difference Method and Characteristic Polynomial Analysis Method. In Case of Convection-Diffusion Equation without Source Terms.

Abstract

A new method of Finite Variable Difference Method (FVDM) is presented. The feature of this method exists in a procedure to determine the finite spatial difference, in which the total deviation of the numerical solution from the exact solution is minimized, under the condition that roots of the resulting characteristic equation are always non-negative to insure numerical stability. The optimum spatial difference of the LECUSSO scheme for the linear convection-diffusion equation is numerically derived in terms of mesh Reynolds numbers. This optimization highly improves the numerical accuracy of the LECUSSO scheme for linear convection-diffusion equations without numerical oscillations at sufficiently large mesh Reynolds numbers of up to 1,000.