rngke or rsm is better than ke model, but can ke catch the secondary flow?

Why no one answer my question?

Yes, but only pressure induced.

For shear-stress induced secondary flows (e.g. swirls in the corners of a rectangle croos-sectiuon) you have to use RSM.

Volker

thanks, but can you tell me more about the difference between second flows induced by pressure and shear-stress?and some references is welcome.thanks again.

with k-eps you can model secondary flows like swirls happen to exist behind backward facing step (cross-section increase). Such eddy water situations are caused by pressure differences.

The secondary flows which cannot be covered by k-eps, are those which happen to appear in non-circular ducts. Two eddies in every corner can be obeserved.

Literature: Every good book on fluid mechanics (or dynamics). (e.g. Bird, Stewar Lightfoot, Transportphenomena, there I found the citation of Schlichtigs "Grenzschichttheorie" or Boundary-Layer Theory with eddies in a triangular duct)