[UdoUebel]

Hey guys!

I found an old CFD-Work (2005), in which the author states that the extension of In- & Outlet would improve the simulation results. He justifies that fact through the reduce of abrupt stall due to short in/outlets.

Is that still a proper method to get realistic results?!

Thank you very much!!

[lcarasik]

Originally Posted by UdoUebel

Hey guys!

I found an old CFD-Work (2005), in which the author states that the extension of In- & Outlet would improve the simulation results. He justifies that fact through the reduce of abrupt stall due to short in/outlets.

Is that still a proper method to get realistic results?!

Thank you very much!!

It depends on the case being analyzed but not necessarily "improve results" but improved convergence. This is usually due to outlet boundary conditions being placed within regions large circulation (i.e. backward facing step or a "expansion") which causes a lot of "inflow" to occur on the boundary. This causes issues with the solvers which causes issues with convergence... usually. Inflow extensions is usually a good idea if you are trying to obtain a fully developed flow profile from an averaged velocity or massflow rate boundary conditions. Though that dependents on your specific case.