TABLE OF CONTENTS In this subsection we provide two turbulence models commonly employed in the compressible flow calculations. Before discussing these models we write the Reynolds stress term and turbulent heat flux term in terms of turbulent eddy viscosity as
and
One of the following turbulence models may be employed to calculate the turbulent viscosity.
In this model the turbulent eddy viscosity is calculated as
where
with
The viscosity variable 
is calculated from
The parameters used in the above equation are written as
where y is the distance from a given node to the nearest wall, 
is the vorticity given as
is the difference in velocity between the point and trip, y t is distance from a node to a trip point or curve, 
is the vorticity magnitude at trip point or curve, ? x is the surface grid spacing at trip. Other constants used in the model are c b1 = 0.1355, c b2 = 0.622, ? = 2/3, K = 0.41, c w1 = c b1/ K 2 + (1 + c b2)/ ?, c w2 = 0.3, c w3 = 2, c v1 = 7.1, c t2 = 2, c t3
