The figures below show velocity vectors and the pressure distribution of the flow past a backward facing step with Reynolds number Re=300. Parabolic profile on the inflow was enforced and the flow was assumed incompressible.

The ElmerSolver uses a stabilized finite element formulation to solve the incompressible Navier-Stokes equations. In this simulation quadratic quadrilateral finite elements were used.

If you want to reproduce the results, download the file Step.tar.gz and follow the instructions in the file README. You should have the Elmer package installed in your computer, however.

When triangular finite elements are used, the user can activate an adaptive (residual based) solution algorithm. ElmerSolver will then automatically refine the initial mesh such that the desired accuracy is obtained with the minimal computational work. This animation shows a sequence of triangulations produced by the adaptive algorithm of ElmerSolver. Note how the mesh is refined locally towards the angle of the step and left coarse close to the outflow boundary.