The velocity field and pressure have been solved successfully in Run # 1. When we solve for the FREE SURFACE (one FREE SURFACE) based on the previous run, the velocity and pressure just go crazy and the solution diverge rapidly with (N.R.) Solver. Also, some of the Node move to certain direction and the next one or two move to the oposite direction. Is there any advice????.

Dear Dr. Hasseneen,

I assume from your brief description that your initial mesh may be far away from the final free surface shape. Since the N.R. solver will make some large corrections to the mesh shape right away, it is quite possible that the calculation will diverge on the first iteration. It is also quite possible that there is an error in the setup of your free surface problem.

One way to get check this is to set the number of iterations to 1 and set the relaxation factor for the free surface to 0.99 or 0.999 (so that it won't change much). Then you should be able to obtain a solution for the first iteration. Take a look at this solution in FIPOST to make sure your problem setup is correct.

Please try this. If it doesn't help, please contact me directly at ewg@fluent.com.

Best regards,

Eric Grald

Thanks Eric for your reply. The problem was in the PRBLEM definition, I was using STEADY and It should be TRANSIENT for the FREE SURFACE calculation. Is that correct?? I will send you the same message directly to you. Thanks Ahmed