surface roughness
 

Hello.
I was simulating the behaviour of a water droplet on an inclined surface. Up to now I've been using InterFoam solver, making the assumption of laminar flow. I specified the contact angle in the o/alpha1 script and gave no other parameters. I now need to model a rough surface. I was thinking of going on with InterFoam but using a turbulent model (a standard k-epsilon model). I've read that the surface roughness can be implemented in the o/nut file by using the nutRoughWallFunction. Does this make sense in my case? What else do I need to change in the model if I use a turbulent model?
I tried to lunch a couple of simulations using this model but i ended up with a fatal error after some iterations. The problem is linked to the adjustable Delta T. Could it be linked to an error in the boundary conditions?
Please, any help is really appreciated.
Thanks.