# Divergence of VOF wave simulation using RANS k-omega model

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 July 11, 2023, 11:03 Divergence of VOF wave simulation using RANS k-omega model #1 New Member   George Tony Join Date: Jul 2023 Posts: 1 Rep Power: 0 Hello, I am conducting a wave simulation using the VOF technique for free surface interaction and is using the k-omega model for turbulance. The waves generated are according to stokes 5th order theory. The computational domain is 24m in length, 1m in width and 2m in height. The boundary conditions used were, inlet - velocity inlet outlet - pressure outlet side1 - symmetry plane side2 - wall (No slip) top - pressure outlet bottom - Wall (no slip) For the free surface, the mesh was generated as suggested by the STAR-CCM manual, that is using 1/80 of wavelength as the base size for the plane lying parallel to the freesurface and using 1/20 of waveheight as the base size for the vertical direction. The time step condition was also calculated using the equation provided by the STAR-CCM manual (T/2.4P). This was used as the initial time step for the analysis, as i was using adaptive time stepping here. The maximum courant no condition was 1. A VOF wave damping criteria was also given at the outlet with a boundarry lenght of 2m (1*wavelegnth). This simulation is done as an intial step so as to check wether the wave generated and the specified wave correlates or not. But after running the simulation for a time of 25 sec with an inner iteration of 10, the residuals in the simulation seems to diverge. Also the wave height measured at the middle of the tank doesnt match accurately the given condition. Is this issue due to wave reflection or is it something wrong with the boundary condition? Wave parameters given wave height - 0.15 length - 2 time - 1.13 Screenshot 2023-07-11 155922.jpg Screenshot 2023-07-11 160000.jpg

 Tags stokes5thwave, vof multiphase