PIMPLE fvSchemes
 

Hello, can anyone explain me please what’s the difference between using PIMPLE with ddtSchemes in SteadyState and, for example, with ddtSchemes in Euler?
Like, do they end up with the same/similar steady state value?

Check out: https://www.cfd-online.com/Forums/op...te-pimple.html

Thank you but I’ve read it and I think I still have the same question. I don’t know If I just didn’t understand the thread but from what I understand in this thread it was more about comparing steady state PIMPLE with SIMPLE no?
I am working on a case and I ran PIMPLE both in steady state and in transient and I pretty much got the same result (despite in transient needing a LOT more time to get the results) and I was wondering If I could just use the steady state.

Yes, absolutely - use a steady state solver/approach if you can, i.e. if your solution is steady state and doesn't include other factors like buoyancy. My experience is that it's always quicker to do so.

Some steady flow flow types are more of a pain to solve, eg buoyant fire plumes etc, since even though the overall solution is steady, there is inherent unsteadiness in the flow that can get worse the more accurate your simulation is. In those cases, it can help to run a transient or LTS simulation.

As for the difference - it's very simple, using a steadyState ddtScheme just sets the temporal derivatives in the transport equations to zero, ie solves for a steady solution (it it exists).

Thank you very much! I will probably put one or two cases in transient just to prove in my thesis that it gets the same and will run everything in steady state.