Gamma Theta Transitional Model

What is the meaning of gamma values >1 and up to the value of 2 in a gamma theta transitional model? Does the gamma theta transitional model work for internal flows?

Values of gamma > 1 are used as a correction to the SST model in separation regions.
SST tends to overpredict the length of separation and using gamma = 2 introduces some additional production of turbulence and therefore the length of separation is corrected.

The gamma theta transitional model will work even in pipes but only in the areas where the boundary layers are developing, not in the areas of fully developed boundary layers.