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 Ardalan June 1, 2010 18:40

I've written a finite volume code to solve 2d incompressible navier stokes equations on a flat plate.
rhi-chow interpolation is used to overcome pressure- velocity decoupling
so the code uses a collocated scheme and simple algorithm for pressure and upwind for convection terms and central for diffusion
the boundary conditions are as follows:
- no slip velocity at the wall
- at the leading edge of flat plate v=0, u=1
- zero velocity normal gradient at the other two boundaries
- zero normal gradient for pressure correction equation at all boundaries

the solution procedure which I have used is as follows:
initial values: u=0.5, v=0.01, p=0
in each pressure correction iteration firstly momentum equations are solved in this way:
firstly the mass fluxes across cell faces are computed using the values of previous iteration and momentum interpolations. SOR algorithm solves the algebraic equations then the mass fluxes are updated using the new velocities. this process continues till achieving a convergence for momentum equations.
then the resulting velocity values are used to solve pressure correction equation and the velocities and pressure are corrected

unfortunately after 3 pressure correction iteration the code diverges (the convergence criteria approaches infinity)
can anyone help me? I'm confused and I don't know what is wrong!
I can send the code to anyone who wants to help.

 Ardalan June 2, 2010 18:32

I've run a steady flow simulation but the solution doesn't converge. The pressure seems to oscillate and not stable during the run. Some friends suggest me to run the transient simulation and see if it helps.
Can anybody explain to me why transient simulation may give a better converged solution in this case?

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