Turbulent flows and related heat transfer over a fully developed wavy channel is investigated by a turbulence model. The nonlinear k-epsilon-f(mu) model of Park et al. is slightly modified and their explicit heat flux model is employed. The Reynolds number is fixed at Re-b = 6760 through all wave amplitudes and the wave amplitude is varied in the range 0 less than or equal to a/lambda less than or equal to 0.15. The predicted results for wavy channel are validated by with comparing the DNS data of Maabeta and Schumann [Flow Simulation with High Performance Computers, Notes on Numerical Fluid Mechanics 52 (1996) 227]. The model performance is shown to be generally satisfactory. By using k-epsilon-f(mu) model, the enhancement of heat transfer and the characteristics of turbulent flow in wavy wall are investigated. Finally, the effects of wavy amplitude on separated shear layer and its consequent influence on heat transfer are scrutinized. (C) 2003 Elsevier Ltd. All rights reserved.