Help about equations

[Clausius2]

I have to integrate numerically the next system of partial differential equations, in "r" and "z" coordinates (steady state, cylindrical coordinates):
-Continuity equation
-Momentum equation (with viscous and convection terms)
-Energy equation (with heat transfer, convection, and internal generation terms).
I heard something about Crank-Nicholson method. I have to implement this problem in Matlab or Fortran.
Anybody know about how can I solve this heavy task?
Anybody know about some web where I could obtain a method for solving it, and implemented in the software specified?.

Thanks for answering.

[enigma]

Does it need to be in Matlab or Fortran, or are those the ones you know how to use?

It may be easier in Mathematica (my new favorite tool).

[Clausius2]

To be honest, Matlab is my useful program. I've been working with it very usually. I don't know anything about Mathematica.
This is the heaviest problem I've never simulated numerically.It is a part of a study of "deflagration initiation by hot jets".

[Clausius2]

I'm looking for a website holding worked programs of CFD. Do you know anyone?. I'm too lazy to do the program on my way!