Implementation of a Fictitious Absorbing Layer for Two-Dimensional Vorticity Equations Based on the Perfectly Matched Layer

Abstract

Abstract. Based on the Perfectly Matched Layer which is often used in wave equations, a fictitious absorbing layer is implemented in the nonlinear vorticity equations, a reduced set of fluid equations. It is shown that the fictitious absorbing layer is effective for the vorticity equations by introducing residual ratio for the theoretical guidance, and by making finitedifference numerical simulations of two examples, translational motion of vorticity and von Karman vortex street. Optimal absorbing coefficient is not determined merely by the theoretical estimate of the residual ratio, but depends on both grid size and accuracy of discretization.