Investigation of Flow and Heat Transfer Characteristics in a Wavy Channel with Varying Amplitude Ratio

Heat exchangers play a vital role in modern industrial systems, where improving heat transfer efficiency is essential for reducing energy consumption, minimizing costs, and supporting sustainable operations. Wavy-wall channels are of particular interest because their geometry can influence flow and heat transfer characteristics. In this study, the effects of the amplitude ratio and the Reynolds number in a wavy-wall channel are investigated with respect to the skin friction factor, streamline patterns, temperature contours, and the Nusselt number. The results indicate that increasing the amplitude ratio (α) enhances heat transfer by intensifying the recirculation zones and thermal mixing, leading to higher Nusselt number. The peak value of the Nusselt number occurring in each wavy passage exhibited an average increase by a factor of 2.6 for the largest amplitude ratio (α = 0.35) at Reynolds number Re = 1×10³. Furthermore, the influence of the amplitude ratio (α) becomes more pronounced at higher Reynolds numbers, as the laminar-to-turbulent transition shifts further upstream. However, this heat transfer enhancement is accompanied by an increase in the skin friction factor (C_f), highlighting the need to evaluate and justify the practical implementation of wavy channels for specific applications.