2D Arbitrary Shaped Particle

[Jijo]

Hello OpenLB developers,

I wanted to ask how can I can select the arbitrary shaped 2D particle (addResolvedArbitraryShape2D())? my goal is modeling an ellipse in 2D as a particle. If that is not possible, which source files should I target to include my own shaped particle?

Your help in the matter is appreciated.
Regards

• This topic was modified 1 month, 3 weeks ago by Jijo.

[Jijo]

Hello OpenLB community,

An update for the above question. when I try to use any shape other than circle in 2D, a rotation matrix is required. How can I implement a rotation matrix? A bit confused here.

Regards,

[jan]

Dear Jijo,

I believe it would be possible to add explicit functionality for this, but the corresponding indicator, smooth indicator and creator function are not currently implemented.

You could use `setResolvedArbitraryShape2D’ as you mentioned, but you should be aware that it discretizes the geometry and therefore introduces some errors, and it’s also likely to be a bit more computationally expensive.

The missing rotation matrix comes from the PARTICLETYPE. In the dkt2d example, typedef ResolvedCircleWithContact2D PARTICLETYPE; is set. As you can see, it explicitly mentions circle because a circle is rotation invariant. So if you want a different shape, please use typedef ResolvedParticleWithContact2D PARTICLETYPE; instead. See src/particles/descriptor/particleDescriptorAlias.h for more aliases. You could also just combine different fields you need in the same way as it’s done there.

Best regards,
Jan

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