A hybrid numerical method for three-dimensional spatially-developing free-shear flows

Abstract

The present novel algorithm for 3D incompressible Navier-Stokes equations treats a domain which is (1) infinite in the vertical direction, using a mapped spectral method; (2) finite in the streamwise direction, using a classical Fourier method; and (3) homogeneous in the spanwise direction, using high-order compact finite differencing. A projection method is employed which ensures the exact conservation of mass, as well as the satisfaction of the boundary conditions at infinity. The novel aspects of these methods are noted, and the code they constitute is validated in light of several test cases. Results are presented for two- and three-dimensional mixing layers.