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-   -   VOF model (http://www.cfd-online.com/Forums/fluent/47829-vof-model.html)

heri April 7, 2008 04:15

VOF model
 
I'm a spanish engineer student and I've some problems with development of VOF model in Fluent (3Ddp) and I need some help. I'm trying to simulate the free surface behaviour in a mold containning liquid steel, i.e., two different phases (air and steel) are required. The steel jets into the mould cavity througha nozzle. I chose liquid steel as phase1 and air as phase2. Previously, I selected VOF model with Geo-Reconstruct Scheme such as an unsteady problem. Then I adapted the region and I patch it as phase2. When I start the iteration process divergences occur at few iterations. Other settings:

Unstructural mesh with tetraedral cells ( Max Skew: 0.84, 132295 cells) Energy Equation (marked) Boundary conditions: Velocity Inlet Pressure outlet Walls Viscous model: k-epsilon standard Discretization: Pressure-Velocity Coupling: PISO Pressure: Body Force Weighted


Renato Pacheco April 7, 2008 14:36

Re: VOF model
 
divergence in VOF models happened to me with poor mesh or with not so small time step size.

sudhir April 8, 2008 02:08

Re: VOF model
 
change the phases.give air as primary phase and liquid iron as secondary phase.

heri April 9, 2008 05:03

Re: VOF model
 
I've tried what you posted, but the solution still diverge. Fluent shows me the follow warning: ''Error: Floating point error: overflow''.

samnetmoon April 9, 2008 18:09

Re: VOF model
 
hi, me too i am a student engineer, i am working on the same work, if you would like to help you send me you gambit and mesh file, and tutorial if you have i will help you if god willing...

Gaurav Mehra April 21, 2008 06:02

Re: VOF model
 
Hi. Samentmoon and heri! I am exactly stuck in the same problem. tracking the same free surface of fluid inside a cylinder with air water being two phases and injecting water from bottom inlet. My cylinder is submerged in the water (80 cm cylinder , 50 cm inside water) I am giving velocity or pressure at the bottom water particles and trying to see the effects on the free surface of it.Kindly tell me if you have got any solution of the problem. I am facing the same error when I try to iterate- " fatal floating point error" I think we are making some value either too small or two big. and by the way we can personally mail each other and chat on some messenger. my email id is NA04B011@smail.iitm.ac.in

heri April 22, 2008 11:02

Re: VOF model
 
Hi Gaurav, I've been studied some VOF examples and I think we could try to add a dynamic grid adaptation. This option could be razonable for control volumes. Regards.


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