2d CFD solver for convection dominated flows

Tiziano

I am trying to write a CFD solver for a convection dominated flow. I decided to discretise the advective fluxes with an upwind approach and to use an explicit approach for the time discretisation. However, while the code works in 1d, I have problems with the second dimension. I assume the problem is that the flow is more or less oriented along the first dimension (I am simulating the flow in a duct).

Any practical suggestions on how to solve this problem? Or any open source CFD solver to suggest? (P.S. the problem is compressible ...)

Thanks in advance ...