sudden expnasion and contraction losses

Babu

Hi all:

I would like to know wether the CFD code captures sudden expnasion and contraction pressure losses in the solver? If so how is it calculated, which is that term. Curious to know.

If the answer to the above question is "yes", then why we are building loss models seperatly for some critical regions such as tip clearance, and so on.

I heard we manually insert some loss terms for a complex turbulence models. Why is it ncecessary, if the solver is capable of doing so (neglecting 100% accurate prediction in wall shear).