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Numerical Study of Heat Transfer Augmentation of Viscous Flow in Corrugated Channels

The convective heat transport characteristics of subcritical and supercritical flows in periodic two-dimensional corrugated channels are investigated numerically using the spectral element method. Computations were performed in the Reynolds number range of 50-800 and Prandtl number of 1. for corrugation angles of γ = 20° and γ = 30°, and for wall spacing-to-periodicity length ratio of b/L = 0.15-0.4. The critical Reynolds number for onset of time-periodic, self-sustained oscillatory state decreases with increasing corrugation angle and with decreasing b/L ratio. The natural frequency of these oscillations is computed, and it corresponds to the least stable subcritical mode (Tollmien-Schlichting frequency) compatible with the given periodic geometry. The transport of heat and momentum due to the supercritical steady periodic states in the corrugated channel are investigated, and the relevant time- and space-averaged Nusselt number and friction factor are calculated