[areje]

Hello all,
Although I look around on this topic I did not find useful explanation how Navier-Stokes equation (i.e. momentum equation) is actually modified in order to take into account laminar viscous regime - i.e. which part of N-S equation is omitted or modified?

I hope I am clear. Thanks in advance for your support.

[areje]

Hello again,
If I am not wrong, I found the answer myself: the "stress part" in RANS is superposition of laminar (viscous) and turbulent (Reynolds) stress --> so in case of laminar viscous regime, turbulent stress is omitted.

[me3840]

Originally Posted by areje

Hello again,
If I am not wrong, I found the answer myself: the "stress part" in RANS is superposition of laminar (viscous) and turbulent (Reynolds) stress --> so in case of laminar viscous regime, turbulent stress is omitted.

Yes, this is true, but it's not really the answer to your first question. RANS was created to deal with turbulence, so it doesn't make sense to use the RANS equations as a starting point for your question.

The regular navier-stokes equations already model laminar flow as-is, no modifications are necessary.

[areje]

Thanks for your reply. Indeed, I was wrong because I mixed NS and their averaged solutions (RANS).
So, choosing "Laminar" viscous regime in the software, we actually choose DNS? Then, just the mesh density plays important aspect...weather to capture every minor flow detail or not?

Thanks in advance.