A two-dimensional steady developing fluid flow and heat transfer through a periodic wavy passage were studied numerically for a fluid with a Prandlt number of 0.7 and compared to flow through a corresponding straight (parallel-plate) channel. Sinusoidal and arc-shaped configurations were studied for a range of geometric parameters. At low Reynolds number, the two geometric configurations showed little or no heat transfer augmentation in comparison with a parallel-plate channel. In some cases the heat transfer enhancement ratios were as high as 80% at higher Reynolds number. An increase in either the height ratio or the length ratio for both sine and arc-shaped configurations resulted in a decrease in the recirculation size and strength. Periodically fully developed flow was attained downstream of the first module of the six modules considered in this study. Copyright © Taylor & Francis Inc.