OpenFOAM: simulation of flow in a valve using simplefoam

[spacefun]

Hi all,
I'm a newbie to use OpenFOAM.
I want to simulate a flow in control valve to measure its Cv, as steady and incompressible conditions.
I set the pressure at inlet and outlet, and I want to get the velocity of flow and so the flow rate.

I create a simplefoam case, I imported the mesh from Salome and I run some first trials.

What I get is:

Floating point exception (core dumped)

after time=10.


It should mean the solver diverges. What I don't understand is how to solve the problem.

Could you suggest me some relaxation parameters to improve the solution and getting the convergence?

Thanks