Fully developed flow structures and heat transfer in sine-sraped wavy channels

Fully developed unsteady fluid flow and heat transfer are studied numerically in a sineshaped wavy channel by solving two-dimensional Navier-Stokes and energy equations. The flow in the channel has been observed to be steady up to a critical Reynolds number which depends on the geometric configuration. Beyond the critical Reynolds number a self-sustained oscillatory flow has been observed. The effect of variations of minimum height, amplitude and wavelength are studied. Decreasing channel height and increasing amplitude cause the flow to become more unstable and thereby increase friction factor and heat transfer, but variation of wavelength has minimal effect. The frequencies of oscillations are reported as well. (C) 2004 Elsevier Science Ltd.