[snappyHexMesh] Holes in cylinder AMI snappy 2.3.0

pbachant · February 27, 2014, 12:45

I am having trouble creating a valid AMI surface from a cylindrical STL with the newest snappyHexMesh. I am using similar settings that have worked in 2.2.2, but with some modifications to mimic the 2.3.0 version of the propeller tutorial (which I think is basically that the AMI is created using createPatch, instead of topoSet). Anyway, I am getting "holes" in the AMI surface that are hard to avoid. I have even tried recreating the dict from scratch using the generic snappyHexMeshDict included with 2.3.0, but still have problems with removing faces (or just never creating them) on the cylinder.

Note I am running snappy in parallel on 6 processes. Any tips for getting rid of these holes?

cutter · March 14, 2014, 08:07

Hi,

how does your initial background mesh look like? Have you tried to increase the bounding box just a little bit in each coordinate direction?

Cutter

pbachant · March 14, 2014, 12:03

Quote:

Originally Posted by cutter

Hi,

how does your initial background mesh look like? Have you tried to increase the bounding box just a little bit in each coordinate direction?

Cutter

My background mesh is a simple rectangle built out of cubes. I have only been playing around with the number of cells in the blockMesh, not the size. Why do you recommend stretching the size?

pbachant · March 14, 2014, 21:37

Seems I have found a way around this problem. Luckily, I was free to change the length of the cylinder to make it 3/4 the height of the blockMesh, then cut the blockMesh in the z-direction such that some existing cells would be coincident with the end faces of the cylinder.

February 27, 2014, 12:45	Holes in cylinder AMI snappy 2.3.0	#1
pbachant Senior Member Pete Bachant Join Date: Jun 2012 Location: Boston, MA Posts: 173 Rep Power: 14	I am having trouble creating a valid AMI surface from a cylindrical STL with the newest snappyHexMesh. I am using similar settings that have worked in 2.2.2, but with some modifications to mimic the 2.3.0 version of the propeller tutorial (which I think is basically that the AMI is created using createPatch, instead of topoSet). Anyway, I am getting "holes" in the AMI surface that are hard to avoid. I have even tried recreating the dict from scratch using the generic snappyHexMeshDict included with 2.3.0, but still have problems with removing faces (or just never creating them) on the cylinder. Note I am running snappy in parallel on 6 processes. Any tips for getting rid of these holes? Last edited by pbachant; March 1, 2014 at 13:40.

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March 14, 2014, 08:07		#2
cutter Senior Member Join Date: Mar 2010 Location: Germany Posts: 154 Rep Power: 17	Hi, how does your initial background mesh look like? Have you tried to increase the bounding box just a little bit in each coordinate direction? Cutter

March 14, 2014, 21:37		#4
pbachant Senior Member Pete Bachant Join Date: Jun 2012 Location: Boston, MA Posts: 173 Rep Power: 14	Seems I have found a way around this problem. Luckily, I was free to change the length of the cylinder to make it 3/4 the height of the blockMesh, then cut the blockMesh in the z-direction such that some existing cells would be coincident with the end faces of the cylinder.