BACKWARDSTEP
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)^2
      
Side 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 = 0
      
where nu is the kinematic viscosity.

Licensing:

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

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


Last revised on 23 July 2015.