The figures below show velocity and pressure distributions of the flow past a cylinder with Reynolds number Re=1000. From the figures the typical rotational flow patterns called Von Karman vortices are cleary visible. With increasing Reynolds number the flow in this kind of configuration becomes unsteady (take a look at the mpeg animation) and finally chaotic.

The flow was modeled with the time dependent compressible Navier-Stokes equations together with the equation of state for ideal gas.

The ElmerSolver uses a two level RFB (Residual Free Bubbles) stabilization technique for compressible flows. In this simulation biquadratic finite elements were used. Newton iteration was used to resolve the nonlinear dependencies in the Navier-Stokes equations within each timestep.

Here you can download an animation of the results mpeg: [~850 KB]