Standard K Epsilon and Transitional SST models
 

can someone please explain to me / link a website / reference a book to explain in relativly "simple" english how these models actally work? and how the maths works for them?

Cheers

Robin.

For Menter's model try this:

Transition Modelling for General Purpose CFD Codes by F. R. Menter , R. Langtry and S. Völker

For k-epsilon you could use any good CFD books like:

Wilcox - Turbulence modeling for CFD

Do