Imposing normal boundary conditions

[raphaelouillon]

Hi all,

I have seen this question discussed here and there but I am not sure if the answer has changed with more recent updates to the code: Is there a reasonable way to impose an inflow (normal flow) boundary condition? If I understand correctly, there isn't a real outflow boundary condition, but imposing the normal flow velocity at the inlet and outlet, and adding a sponge layer at the outlet can do an ok job. Do we have an example of such a problem somewhere? A good old flow past a cylinder for instance?

Thanks for your thoughts on this!

[glwagner]

It's not really supported, but you can try to use OpenBoundaryCondition(1), for example. You should write some validation tests to see if this works and report results here.

However, since we have to impose a sponge layer anyways, it may make more sense to use Periodic boundaries and impose the inflow via the sponge layer at the "outlet". This works for simple / periodic inflow+outflow conditions.

[raphaelouillon]

Thanks @glwagner , the sponge approach seems to be working well!