[AndrewMortimer]

Hi all,

I'm essentially running the turbine_siting tutorial but with different geometry. There are 2 different types of output from the setup:

- The flow only goes over the hill as desired. This is shown in pic 1. This was achieved with a surface refinement of 2


- The flow goes under and beneath the hill as shown in pic 2. This occurred with a surface refinement level of 3.

In both cases the blockMeshDict was the same:

vertices
(
        ( -3000.0 -3000.0 -400.0) 
        ( 5000.0 -3000.0 -400.0) 
        ( 5000.0 5000.0 -400.0) 
        ( -3000.0 5000.0 -400.0) 
        ( -3000.0 -3000.0 600.0) 
        ( 5000.0 -3000.0 600.0) 
        ( 5000.0 5000.0 600.0) 
        ( -3000.0 5000.0 600.0) 

);

blocks
(
    hex (0 1 2 3 4 5 6 7) (40 50 20) simpleGrading (1 1 1)
);

although I have found that varying the number of blocks in the z sometimes changes the output.


The model I have for the hill is an stl and is essentially just a single sheet, i.e it is not a closed model.

Does anyone know why sometimes the flow doesn't go under the hill and sometimes it does? These are the only settings I've been playing around with.

Thanks in advance.

[linnemann]

Hi

You probably have a crack/hole somewhere on your stl file that is larger than refinement level 3.

That will let the mesh "flow" through the crack and also mesh the volume below the surface.

So make sure your STL extends a little beyond the blockMesh mesh.
After that make sure there are no leaks in your stl.

[AndrewMortimer]

That was indeed the problem. Thanks for the help!