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-   -   FLUENT VOF for ship's hull (http://www.cfd-online.com/Forums/main/16070-fluent-vof-ships-hull.html)

simone b. December 1, 2008 11:23

FLUENT VOF for ship's hull
 
Hi everyone, I'm trying to simulate the flow around ship and I use multiphase flow VOF in FLUENT for analize this type of problem. I use a fully hexa mesh with high qualty ( determinant 3x3 from 0.6 to 1) generated with ICEM CFD

My setting is Reynolds Stress Model, VOF Implicit with open channell formulation, seady state I've tryied a k-w SST viscous model too.

I have some problem about this simulation:

1) My simulation diverge with k-w SST, and with the RSM i need to decrease more the under relaxation factor (0.15 max)

2) If i try to simulate a case with y+=50 or less, after 200 iteration the simulation diverge.

What can i do?? What type of setting is required??

If someone have any information or solution fot this type of problem please send me at my email : simone.bartesaghi@alice.it

Thank's for attention.

regards, simone

simone b. December 2, 2008 04:30

Re: FLUENT VOF for ship's hull
 
Anyone can help me?? Please i'm in very difficulties....

Bikini Girl with Machinegun December 2, 2008 06:24

Re: FLUENT VOF for ship's hull
 
1. Nobody will be able to help you when you give very few details about your problem.

2. People help when they can. You can't hurry them because you have a deadline.

3. You are using CFD on ship problems. Haha! Which idiot talked you into doing that?


Julien December 2, 2008 06:53

Re: FLUENT VOF for ship's hull
 
A little harsh, don't you think Bikini Girl?

The guy is desperate and needs help. Plus, he did a reasonable job of explaining his problem, at least enough to get a discussion going. Unfortunately, I do not use Fluent, so I can't help.

I'm guessing the Fluent tech support was of no use?

Charles December 2, 2008 13:29

Re: FLUENT VOF for ship's hull
 
The most helpful answer I can give you is to underrelax the solution dramatically until it has stabilised. When I say dramatically, I mean that for the segregated solver you would be looking at relaxation factors of 0.05 or so, and for the coupled solver a CFL < 0.2. Some solutions will only work with the coupled solver. If you are desperate, give me some money and I will do it for you :)


Ranga December 6, 2008 07:45

Re: FLUENT VOF for ship's hull
 
Its seems to be tough in fluent using VOF. I think you may switch over to ANSYS CFX 11.0. Robust solver.


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