DFBI embedded mesh

nickd · March 1, 2011, 16:22

Has anyone been using the embedded mesh DFBI model for doing free-surface simulations? I have been trying to set up the model but I seem to have the inner cylinder fixed and the outer domain moving, which isn't what I intended and if I attempt to fix it the other way round it locks it as stationary.

If anyone has any advice or a simple sim file I could have a look at I'd be most grateful.

many thanks,

abdul099 · March 4, 2011, 03:29

I've done it a few months ago and it worked fine. Can you describe your setup a little bit more?
Maybe I've got a simple testcase available which I can send you, but I have to check first.

Cheers

nickd · March 14, 2011, 13:45

Hi Robin,
sorry to take so long to reply.
I'm trying to use an embedded mesh to allow a boat to trim and heave with a free surface. I have the meshing set up ok, but am slightly unsure about which coordinate systems I need for the different zones. I have a volume refinement zone around the free surface, to allow for accurate capturing, but as I'm testing NPL hullforms and want to extend to planing hulls I would rather use the DFBI embedded mesh than the DFBI rotation & translation, which I can run fine, but requires lots of wasteful cells at the exit of the outer domain.
It seems that as the inner mesh is rotating, the angle of the FlatVOFWave at the inlet and outlet changes, which makes me think I have used the wrong coordinate system somewhere. I have a small test sim (300k cells) that I have been playing with, and it runs for a while then blows up and the inner mesh moves through the outer domain. I've not watched it as it happens, so it may just be a symptom of the simulation blowing up as it doesn't seem to do it generally.
If you have a sample sim then I'd be very grateful to have a look.

many thanks
Nick

March 1, 2011, 16:22	DFBI embedded mesh	#1
nickd New Member Nick Dawson Join Date: Nov 2010 Posts: 4 Rep Power: 16	Has anyone been using the embedded mesh DFBI model for doing free-surface simulations? I have been trying to set up the model but I seem to have the inner cylinder fixed and the outer domain moving, which isn't what I intended and if I attempt to fix it the other way round it locks it as stationary. If anyone has any advice or a simple sim file I could have a look at I'd be most grateful. many thanks,

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March 4, 2011, 03:29		#2
abdul099 Senior Member Join Date: Oct 2009 Location: Germany Posts: 636 Rep Power: 22	I've done it a few months ago and it worked fine. Can you describe your setup a little bit more? Maybe I've got a simple testcase available which I can send you, but I have to check first. Cheers

March 14, 2011, 13:45		#3
nickd New Member Nick Dawson Join Date: Nov 2010 Posts: 4 Rep Power: 16	Hi Robin, sorry to take so long to reply. I'm trying to use an embedded mesh to allow a boat to trim and heave with a free surface. I have the meshing set up ok, but am slightly unsure about which coordinate systems I need for the different zones. I have a volume refinement zone around the free surface, to allow for accurate capturing, but as I'm testing NPL hullforms and want to extend to planing hulls I would rather use the DFBI embedded mesh than the DFBI rotation & translation, which I can run fine, but requires lots of wasteful cells at the exit of the outer domain. It seems that as the inner mesh is rotating, the angle of the FlatVOFWave at the inlet and outlet changes, which makes me think I have used the wrong coordinate system somewhere. I have a small test sim (300k cells) that I have been playing with, and it runs for a while then blows up and the inner mesh moves through the outer domain. I've not watched it as it happens, so it may just be a symptom of the simulation blowing up as it doesn't seem to do it generally. If you have a sample sim then I'd be very grateful to have a look. many thanks Nick