[michele]

I'm just starting to use the OpenFOAM. I'm interested in VOF methods for ship hydrodynamics simulations. I had previously used other CFD tools when I worked at University.
The first test I'm making is a very simple undisturbed free surface 2D case. An uniform velocity field enters from the left and, after having crossed the domain, leaves the domain through an outlet boundary condition. I'm using the rasInterFoam, as I'm interested in getting a model more and more sophisticated (the complete simulation will require a 3D full rigid body dynamics for a boat... I would like to make roll damping calculations and performance analyses).

But I must confess I hadn't obtained good results even for this simple problem. The problem is well initialised and starts well. But after about 2.6 seconds the free surface is distorted (I was expecting a trivial solution of steady undisturbed free surface). The link to a picture of gamma is the following:
http://www.lem3.it/tests/gamma_2.57102.png

The process becomes unstable some time after, as can be seen in the following picture:
http://www.lem3.it/tests/gamma_3.15095.png

The time step is limited by a Courant number of 0.2, the fields are initialised accordingly with the boundary conditions...

I was considering what I was missing... Thanks in advance.
Michele.