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-   -   Free surface boundary condition in the VOF metod (http://www.cfd-online.com/Forums/main/84832-free-surface-boundary-condition-vof-metod.html)

ves February 9, 2011 14:33

Free surface boundary condition in the VOF metod
 
I developed main VOF software basic on the SOLA-VOF, VOF-2D, but preesure do not convergence (breaking dam simulation)
First variant main software based on the method artificial compressibility (pressure do not convergence), second variant based on the projection method (pressure do not convergence), divergence in emty cell adjacent to full cell is too high. Pressure and velocity boundary condition same as SOLA-VOF; SOLA-VOF, VOF-2D breaking dam simulation failed too.

alongalong2 February 10, 2011 01:16

HI Ves
If artificial compressibility is used in N-S equation, the pressure is no possibility to diverge if you write the program based on SOLA-VOF, so i think you need to check your program again.
If the program above can run smoothly, the program based on project method can do so.

Along

ves March 8, 2011 16:23

I am find some mistake in my programs, but they does not work. First program based on the Veldman's sample program, boundary condition for free surface pressure and velocities same as in SOLA-VOF. Second program based on the artifical compressibility. Solving equation:
dU/dtau+dU/dt+grad(U^2)=-1/rho*gradP+F
1/beta*dP/dtau+divU=0;
beta=1-relaxation parameter;-tau psevdotime;
iteration: internal cycle tau while divU>eps, external cycle t. boundary condition for free surface pressure and velocities same as in SOLA-VOF.
VOF in both program based on Hirt-Nichols local-height function or free surface normal.
Navier-Stokes good work (shear cavity), VOF good work (Zalesyak test), Navier-Stokes +VOF+free surface boundary condition does not work. Why? Help, please.


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