[Thomas Sprich ZA]

Hi Adrian,

I have managed to do as you suggested and have created an example where the particle dynamics have been modified. I have centered the domain, used only one cube and located it centrally. It rotates about the z-axis. Its very crude at this stage. I have essentially added particle dynamic classes in the simulation file as I did not want to modify/add to the core code base.

I am happy to share it with you if you would like to add it to the examples. What would be the best way of doing this?

The next step I’d like to implement is to define the particle using an stl file. Could you give me some pointers how to achieve this? From the settlingCube example, the particles is created with the addResolvedCuboid3D function defined in particleCreatorFunctions3D.h. In particleCreatorFunctions3D.h, there are other functions such as setResolvedArbitraryShape3D which I thought might be applicable. Am I on the right track?

For my next question, I foresee a potential issue where the geometry I intend to use will have thin sections relative to the overall domain. This arises due to the plate thickness being thin and capturing such thin section would require a dense lattice. This is obviously challenging in big domains. I see there is also subgridObjects in the particleCreatorFunctions3D.h file. Is this a valid approach to dealing with the thin sections. Otherwise, is it possible to do local lattice refinement enclosing the region within which my object rotates? Do you have any other suggestions for this kind of problem. It must come up frequently.

Lastly, I see in the version 1.6 release notes that the particle examples do not work with CUDA. Are there plans to expand the CUDA functionality to include these examples? This could also help address the dense lattice issue discussed above.

I would love to join your spring school. I however live in South Africa, so it becomes costly to attend in Germany.

I look forward to your answers.

Thanks,
Thomas

[Thomas Sprich ZA]

Hi Tim,

No apologies required. I’m just glad you are aware of the problem.

Good luck resolving it.

Regards,
Tom

[Thomas Sprich ZA]

Hi Adrian,

Thanks for the tip to check HLBM, I will definitely take a look.

Yes, my plan was to adapt that example as you suggest. Its not obvious to me how to define the dynamics. I only skimmed through the user guide though, so perhaps I should read more carefully.

I will let you know here if I make some progress.

Thanks again for the tips.

Regards,
Thomas

[Thomas Sprich ZA]

Hi Adrian,

I am also interested in this topic. I have looked settling cube example and thought that this approach might work for rotating geometries. Is this what you were referring to?

I also have very limited LB knowledge, but from my initial reading, it seems that the immersed boundary method would be appropriate to this kind of application. It is just not obvious to me how to prescribe the motion and handle the forces correctly.

OpenLB is obviously an complex code, but if you could provide a few pointers where to look it would help a lot. I would be happy to try an put together a simple example, which if good enough could be added to OpenLB. My thoughts would be to start with a spinning cube or square in 2D.

Please let me know if you have any advice.

Regards,
Tom

[Author]

Posts