Set Pressure Boundary Conditions for Inlet and Outlet

[taki]

I am trying to simulate flow driven by a pressure difference between the inlet and outlet using OpenLB. I have attempted to set pressure boundary conditions at the inlet and outlet, but the simulation does not behave as expected. I noticed that others have asked similar questions, but I could not fully understand the solutions provided.

Here are my main questions:

1, Are there any geometry-related constraints for using pressure boundary conditions? For example, should the outlet width be reduced to ensure stability or better performance?
2, Even with the following boundary condition setup, the simulation does not work properly:

// Setting of the boundary conditions
setlocalPressureBoundary(sLattice, omega, superGeometry, 3);
setlocalPressureBoundary(sLattice, omega, superGeometry, 4);

Is there any additional setup or adjustment required to make the pressure boundary conditions work for a steady flow driven by a pressure gradient?

Any advice or examples would be greatly appreciated. Thank you!

• This topic was modified 1 month, 2 weeks ago by taki.

[sfraniatte]

Hello,

I attempted to apply these boundary conditions, but it turned out not to be a good idea in my case, as the simulation became less stable. I believe this might explain why there is so little information available on how to implement them. You have likely done everything correctly; it’s just that this approach doesn’t seem to work as intended in this particular situation.

For instance, when I applied these boundary conditions in the aorta example, the flow reversed for certain pressure inlet values.

[Author]

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