it doesnt converge

Beno

Hi!

I am having a little problem with convergence. I am trying to simulate flow through orfice plates, but i cant get cfx to converge. I tried to change physical timestep, but no succes. I altered the mesh by reducing the number of nodes and it converged, then I used this solution for initial values and still nothing. The convergence criteria is 5*10^-4. Equations are 2nd order. If equtions are 1st oreder it converges, but results I get are not what I hoped for. In fact I am trying calculate coefficients for different diameters of orifice plates, but they seem to be quite random. Is there anything else to do?

And another thing: I tried to use symmetry planes but this eksperiment gave totaly different results then the one with the hole domain. Why is that?

Thx for help!

Beno