how to apply low reynold number K-epsilon model in fluent6.2......?????How to start it as there is no direct option available in model menu...

You can use RNG kappa-epsilon which can be applied for both high and low Re. Also enable extra options such as Enhanced Wall Treatment to resolve deeper the flow field if you want. If you apply that be careful to have a refined grid (y+ <5)-use grid adaption.

Good luck, Spyros

Yes, it's ok, maybe y+ close to 1 is very good, but if you can, try to avoid the y+ grid adaptation, I had some problems with that. Sometimes, the better options is to regenerate the mesh.

good luck

you should use the tui command