MultiRegion SnappyHexMesh Workflow for complex geometries
 

Hi all,



I have had great success doing conjugate heat transfer simulations using Salome to perform meshing. However, I wish to have more control and the ability to parallelize my mesh generation.



I have followed the snappyMultiRegionHeater tutorial to explore the possibilities for this. It works great for simple cases. However, my cases are more complex. First off, the method this tutorial uses for multiple regions is that the external boundaries and geometry is set by blockMesh. However, my cases require a complex external geometry as well and I guess I could contain that all in a blockMesh but I rather not due to increased computational time. Secondly, I have several (sometimes hundreds) of regions which are of the same material and separated. With salome meshing, this is easy to make all these regions one region in OpenFOAM and I guess I could make a python script to assign all the region properties and initial conditions, but sometimes I cannot differentiate between which region is which.


So with all that in mind, my two questions are:



1. How can I setup a multiregion snappyHexMesh case with stl surfaces such that one stl determines the exterior bounds? (I know I can do the whole surface then partitions method, but this is tedious for the cad design unless we can figure out the second problem).



2. How can I setup a multiregion case for snappyHexMesh where several separated geometries are contained in the same region? For example, a random suspension of hollow cylinders in a cube and all the cylinders are the same material and the inside of the cylinders are a different material. The end goal being three regions, the cube medium, cylinder medium, and interior cylinder medium.



Any help is appreciated,



Thanks!

Complex geometry multiregion snappyhexmesh
 

Hie there, please help if you eventually found the solution to your meshing problem. I am trying to model a heat exchanger with complex porous structures which has sides 1 and 2 for flow of hot and cold fluid resp. I have tried to use the shell and tube heat exchanger tutorial to help but i am facing challenges and there are more than 1000 faces wrongly oriented. Free standing faces. Where is the problem exactly with my mesh or anything. Please help.

Solution
 

The best solution here is to model the entire heat exchanger and use toposet (surface) and then setsToZones. This may become complex if your interfaces don't match up, so make sure they do.

I will try that and see if i will get something different. I am also creating my surfaces using blender, its too much work when using blender to make porous surfaces like those. I will give feedback on the progress