[snappyHexMesh] What should I do if don't want to remove the cells inside/outside .stl boundary?

TongX · March 14, 2022, 04:58

I want to use SnappyHexMesh to generate mesh for IBM algorithm. So my idea is to turn off "snap" and "addLayers", and only turn on "castellatedMesh". That is, the final result I want is Fig. 5.11 in https://cfd.direct/openfoam/user-gui...snappyhexmesh/. But I don't know how to turn off the function of removing cells....

AtoHM · March 14, 2022, 05:44

OpenFOAM has that covered. Right at the top, you can specify the steps to run. This should get you the wanted result:

Code:

// Which of the steps to run
castellatedMesh true;
snap            false;
addLayers       false;

https://develop.openfoam.com/Develop...ppyHexMeshDict

TongX · March 14, 2022, 06:52

thanks very much for your reply! I have tried this, the function of "snap" and "addLayers" will be turned off, but the cells in the immersed boundary will be deleted, that's what bothers me. if I delete the "locationInMesh", there will be Error message. But if I set a point outside the boundary in "locationInMesh", there will also be an error says "Point is not inside the mesh or on a face or edge.".

AtoHM · March 14, 2022, 08:46

Ah, you probably need locationsInMesh then: Usage of locationsInMesh (needs the ESI release)
It supports multiple zones and should keep all the cells.

March 14, 2022, 04:58	What should I do if don't want to remove the cells inside/outside .stl boundary?	#1
TongX New Member Tong Xin Join Date: Mar 2021 Location: Shanghai P.R.China Posts: 2 Rep Power: 0	I want to use SnappyHexMesh to generate mesh for IBM algorithm. So my idea is to turn off "snap" and "addLayers", and only turn on "castellatedMesh". That is, the final result I want is Fig. 5.11 in https://cfd.direct/openfoam/user-gui...snappyhexmesh/. But I don't know how to turn off the function of removing cells....

March 14, 2022, 05:44		#2
AtoHM Senior Member M Join Date: Dec 2017 Posts: 703 Rep Power: 13	OpenFOAM has that covered. Right at the top, you can specify the steps to run. This should get you the wanted result: Code: // Which of the steps to run castellatedMesh true; snap false; addLayers false; https://develop.openfoam.com/Develop...ppyHexMeshDict

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March 14, 2022, 06:52		#3
TongX New Member Tong Xin Join Date: Mar 2021 Location: Shanghai P.R.China Posts: 2 Rep Power: 0	thanks very much for your reply! I have tried this, the function of "snap" and "addLayers" will be turned off, but the cells in the immersed boundary will be deleted, that's what bothers me. if I delete the "locationInMesh", there will be Error message. But if I set a point outside the boundary in "locationInMesh", there will also be an error says "Point is not inside the mesh or on a face or edge.".

March 14, 2022, 08:46		#4
AtoHM Senior Member M Join Date: Dec 2017 Posts: 703 Rep Power: 13	Ah, you probably need locationsInMesh then: Usage of locationsInMesh (needs the ESI release) It supports multiple zones and should keep all the cells.