  Reynolds-averaged Navier-Stokes (RANS) turbulence models (such as k-\epsilon
models) are still widely used for engineering applications because of their
relatively simplicity and robustness. In fully developed plane channel flow
(i.e. the flow between two infinitely large plates), even if available models
and near-wall treatments provide adequate mean flow velocities, they fail to
predict suitable turbulent kinetic energy "TKE" profiles near walls. TKE is
involved in determination of eddy viscosity/diffusivity and could therefore
provide inaccurate concentrations and temperatures. In order to improve TKE a
User Define Function "UDF" based on an analytical profile for TKE was developed
and implemented in Fluent. Mean streamwise velocity and turbulent kinetic
energy "TKE" profiles were compared to DNS data for friction Reynolds number
Re\tau = 150. Simulation results for TKE show accurate profiles. Simulation
results for horizontal heated channel flows obtained with Fluent are presented.
Numerical results are validated by DNS data for Re\tau = 150.
