queries about turbulence

Micheal

Hi to all cfd users. I have gone though fluent help manual,and found follwing queries.Pls if anybody knows then give me a little idea.

(1) I have read in manual that Wilcox K-w model is sensitive to free stream value of B.C.why ?

(2) Why k -e is not good for near wall regions?

(3) what are blending functuions in mentor SST?

(4) Why k -e gives poor results for axi symmetric flows?

Thanking u all

Michael