Water Flow around hull ship : interFoam 1.6.x vs 1.5
 

Hi, i simulated a flow around an hull ship with interFoam (only water, no air and free surface). I have results with v1.5 and they seems really good. I tried to repeat the problem setting up a complete similar case in v 1.6.x but it gives me bad pressure and velocity field (all force coeffs are wrong and the simulation stopped after two days giving me an error ). I d like to know the differences between v1.5 and v1.6.x and if i setted in the wrong way the different params of simulation. I attach a pdf with the principal files.

EDIT: contours of p and U here

http://dl.dropbox.com/u/3617688/contours.tar.gz

Interesting
 

This is interesting. Anyone else facing this problem? Has anyone fixed it?

OF-1.6.x has some really nice features for hull analysis, but unless we figure out what is going on with the results they're useless.

Regards,

Gonzalo

Having a look to your files I found a couple of things that might help, but still I don't think you'll get the same results.

1. In the inlet B.C I found that setting alpha to a constant value with setFields helps convergence.

2. You should also have an atmosphere patch.

3. Try with the hull as bouyantPressure too.

Good luck, although we're still missing something. I wish there was more documentation about interFoam in 1.6.x

Gonzalo

i think i have to change boundary condition on pressure : if in 1.5 i have zeroGradient, in 1.6.x i have to switch on buoyantPressure on the patch orthogonal to pressure gradient. I ll keep you updated on simulation's results. Stay tuned :)

I changed the pressure boundary conditions and now p field seems good. But i have a local "dicontinuity" of U field on symmetry patch. How can i solve it?? I attach the screenshots

http://dl.dropbox.com/u/3617688/Ufield.png
http://dl.dropbox.com/u/3617688/UfieldMesh.png

Hi Emanuele,

That is because unstrured mesh (tetras) is not working nice.

Change your mesh to hexa and if possible structured and you will see everything better.

Hi Emanuele,

could you put your settings for OF-1.6.x ?

Have you improve your calculation ?

Best regards,

Stephane

I have set a less value of Courant number and now it works and it's running on 4 CPUs from two weeks :cool:

Hi Emanuele,

You have a very low Courant Number !

The wigley hull of Eric Paterson runs well with Courant Number 0.8.

Regards,

Stephane.

Do you think i have to investigate what are wrong in other part of the case?? I thought the mesh but checkMesh is perfect...any idea??