CFD Online Discussion Forums - Convergence problem laplacian

Hey guys,

I programmed a little solver for solving the compressible Reynoldsequation.

Code:

 surfaceScalarField  phis = fvc::interpolate(U*h/(R*T)) & mesh.Sf();

 

 { 

     tmp<fvScalarMatrix> PEqn 

       (            

          fvm::laplacian(p*(pow(h,3))/ (12 * (nu)),p)  

 

        - fvc::div(phis,p)  

         );

   

   PEqn().solve();

For a high velocity of the shaft i get highly oscillating results. With a really really low relaxation (0.0001) its converge very slow to the expected Values for p.

My schemes i use are:

Code:

divSchemes

{

    default     none;

  div((interpolate(((Uwelle*h)|(R*T)))&S),p) Gauss upwind;

     

}

laplacianSchemes

{

    default         Gauss linear corrected;

    laplacian(((rho*pow(h,3))|(12*nu)),p) Gauss linear corrected;

    }

I tried to use an upwind scheme for the laplacian term as well but i got some Errors.
How can i discretize the laplacian term with an upwind scheme, and do you have some other ideas to get it stable ?

Thanks,
Daniel :)