MAC for flow over a 2D cyl

Tee

Hi all

I am trying to simulate the flow over a 2D cyl using MAC method for Re upto 100. I am solving the transformed N-S equations on a polar grid. Firstly, I am advancing the eqns(which r in a non consv. and non dimensionalized form) explicitly in time. Then I am solving a pressure correction eqn. However I am not able to acheive convergence.

The B.C's I am using are: no slip on the cylinder, horz. vel specified on the outermost circle(i.e at infinity). What would be the B.C's for the transformed P.C eqn? At the moment I am specifiying pressure on one boundary(ie pressure at inifinity, resulting in pressure correction=0), dpdash/dn=0 on cyl and periodic b.c. Also, does the choice of discretizing scheme affect the convergence as well or just the accuracy of the solution. For e.g if I were to use central diff for the convective terms as well, could I expect convergence? I have tried tinkering with the time step and relaxation factors etc.

Thanks in advance.