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-   -   snapyHexMesh Bounding box (http://www.cfd-online.com/Forums/openfoam-pre-processing/101985-snapyhexmesh-bounding-box.html)

vmsandip2011 May 18, 2012 14:28

snapyHexMesh Bounding box
 
Hi
I have simple question.
Do snapyHexMesh always have a bounding box ?
If we have a internal flow still do we need bounding box and for what reason we need it in internal flow cases.
My another question is how do we select a particular surface for refinement
do we use loctionMesh option for that, is it a starting point of mesh ?
Please reply.
Thanks .

lovecraft22 May 19, 2012 04:44

Hi;
don't know about the bounding box, you should try but I think it needs it anyway.
locationInMesh is a point of the mesh you want to keep. For instance let's say you are running a car. snappyHexMesh wants to know whether you want to simulate the internal of the car (mesh within the car then, where the driver sits) or the external flow (mesh outside of the car, where the air if flowing due to the motion of the car).

About the refinement of the surface, you need to add that surface within the refinementSurfaces such as:

Code:

refinementSurfaces
{
        your_surface_name
        {
            //Surface-wise min and max refinement level
            level (3 3);
        }
}


wyldckat May 19, 2012 17:55

Greetings to all!

About the bounding box: snappyHexMesh needs an already existing mesh to work with and usually a bounding box is the easiest and simplest mesht to start with.
You can think of snappyHexMesh as an semi-autonomous discrete-space sculptor ;) It can chisel, cut, mold, slice (and perhaps splice) cells into the form that corresponds to the criteria required.

Best regards,
Bruno

vmsandip2011 May 21, 2012 11:27

snappyHexMesh Bounding Box
 
Hi Bruno
Thanks for the reply.
I understood that it refines the mesh.

But as I have seen in OpenFOAM tutorials almost all are external flow cases(where snappyHexMesh is used) that is why it is required the bounding box, but is it necessary(bounding box) for internal flow too?

with regards,
Ravindra.

sail May 21, 2012 12:35

Quote:

Originally Posted by vmsandip2011 (Post 362245)
Hi Bruno
Thanks for the reply.
I understood that it refines the mesh.

But as I have seen in OpenFOAM tutorials almost all are external flow cases(where snappyHexMesh is used) that is why it is required the bounding box, but is it necessary(bounding box) for internal flow too?

with regards,
Ravindra.

it doesn't need to be a box, can be any shape you like.

but it does need to have an existing mesh to work with, so even for internal flows the easiest thing to do is to produce a box with blockMesh and start from there.

vmsandip2011 May 26, 2012 02:13

snapyHexMesh Bounding box
 
Thanks for the reply
I have got one such case.

with regards,


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