DNS of 2D turbulent flow around a square cylinder

Two-dimensional 'turbulent' flow around a rectangular cylinder has been simulated at Re = 10,000 using a sixth-order-accurate finite volume method for the discretization of convection and diffusion. The spatial discretization consists of a combination of a seventh-order upwind-biased method for the convective terms and an eighth-order central method for the diffusive terms, discretized on a stretched and staggered grid. To cope with the stretching of the grid, Lagrange interpolations are used. The method applied to obtain a boundary condition for the velocity in the x-direction at the outflow boundary is shown not to affect the flow in the interior of the computational domain in a way that is visible in various snapshots of the vorticity field. The variation in the velocity in the x-direction with time is itself found to be relatively small near the outflow boundary. Several turbulence statistics have been gathered from a simulation of the flow developed during 77 dimensionless time units. Snapshots of the vorticity held of the developed flow show the presence of a vortex-street-like structure. Typical 2D turbulent behaviour, such as the appearance of monopolar, dipolar and tripolar vortices due to the amalgamation of vorticity in the wake and the x(-1/2) scaling of the velocity defect in the wake, has been obtained. (C) 1997 by John Wiley & Sons, Ltd.