Using STL generated from blender

[eaxebx]

Hi, I am trying to set up a simple simulation using a cylindrical tube by importing an STL file for the geometry. I created the tube (center is empty) in blender and exported as an stl file from blender. I am not sure how the units are set in openLB in this scenario. I am also having trouble using such an STL file from blender. Can we have a simple tubular flow example with a stl file created from blender to get the users started? Or if there is an example in openlb that addresses this simple use case scenario? I can email a copy of the stl file if needed. (its geometry is outer radius = 1, inner radius = 0.8, height = 10)

Many thanks!

[mathias]

Dear eaxebx,

the stl must be watertight and no double layers should be there. Have a look at e.g. the e.g. cylinder3d ora aorta3d examples. There is also a section on it in the user guide.

Best
Mathias

[eaxebx]

Hi Mathias, what’s a double layer in openlb terminology?

[mathias]

Two serfaces (i.e. stl triagles) parallel and close to eachother.

[eaxebx]

Hi Mathias, the cylinder3d worked great and I was able to play around with other blender STL files using it. Now I have a new question, is there a way to simulate the movement of the cylinder obstacle in a flow if the cylinder is allowed to move. I understand for the example the cylinder is fixed in place. What does it take to allow the cylinder to move due to the collision from the fluid? We would need to consider its mass (density) and effect of moving geometry. Is there an example in multi-component set up that could be used to set it up? Thanks.

[mathias]

You mean as the 3D particle in https://www.sciencedirect.com/science/article/abs/pii/S0045793018300823 ? That was done done with OpenLB. Best Mathias

[eaxebx]

Mathias, yes something similar, is there an example in openlb I could look at? Thanks,

[mathias]

Similar is the DKT example in the particle folder. This one from the paper has not been released and is not up to date with the latest release. Please contact me be email if you are interested to discuss a colaboration. Mathias

[eaxebx]

Mathias, thanks, let me check the DKT example first and will email you afterwards.

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