A projection method for low speed flows

We propose a decomposition applicable to low speed, inviscid flows of all M ach numbers less than 1. By using the Hedge decomposition, we may write the velocity field as the sum of a divergence-free vector field and a gradient of a scalar function. Evolution equations for these parts are presented. A numerical procedure based on this decomposition is designed, using project ion methods for solving the incompressible variables and a backward-Euler m ethod for solving the potential variables. Numerical experiments are includ ed to illustrate Various aspects of our algorithm. (C) 1999 Academic Press.