modeling turbulent duct flow
 

i am new to cfd , i want to do simulation on turbulent flow in ducts with vortex generator ,to get heat transfer and friction charaterstics.kindly suggest best turbulence model....as vortex generator is inserted ,it involves local flow seperation..so is it ok to try with standard RNG k-epsilon with enhanced wall fn??

I've seen a lot of kw-SST for vortex generators. I've had reasonable results from realizable k-epsilon with enhanced wall functions as well. I don't have much experience with the RNG models, so I cannot say.

On a technicality note, I don't consider the purpose of inserting vortex generators to be the generation of stable separation bubbles but rather the generation of a stable secondary flow (or vortex). For that reason, I would target models that handle secondary flows well and not necessarily separated flow. But there is always the possibility of separated flow, so catch 22.