The Backward Step Benchmark for Navier-Stokes Flow

**BACKWARDSTEP**,
a FreeFem++ script which
solves the backward step benchmark problem for Navier Stokes flow.

The backward step geometry is:

| y=H +--------------L5--------+ y=H | | | | L1 L2 | | | | y=0.5 +-L4--+ | | L4 | | y=0 +--------L3--------+ y=0 | ^ ^ ^ | x=0 x=3 x=22 | +--------------------------------------------------In flow case 1, H = 1.5, and in flow case 2, H = 1. Solutions are desired at Reynolds numbers 50, 150, 500. Side L1 is an inflow boundary, with a parabolic inflow profile:

uinflow = (H-y)*(y-1/2)/((H-1/2)/2)^2Side L2 is an outflow boundary where boundary conditions are not imposed. Sides labeled L3, L4 and L5 are no slip walls, with U = V = 0.

The steady incompressible Navier Stokes equations for (u,v,p) in 2D are:

-nu ( uxx + uyy ) + u ux + v uy + px = 0 -nu ( vxx + vyy ) + u vx + v vy + py = 0 ux + vy = 0where nu is the kinematic viscosity.

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

- backwardstep.edp, the FreeFem++ script;
- backwardstep.sh, a BASH script to run the example;
- backwardstep_output.txt, the output file;
- backwardstep_mesh.png, a PNG image of the mesh;

You can go up one level to the FreeFem++ web page.