Influence of frequency and intensity of bilateral audible sound waves on heat transfer performance of air-to-air heat exchange systems

•Bilateral audible sound waves are incident to enhance the air heat transfer.•Change in SPL and frequency has different effects on the flow instability.•Relationship between local heat flux and flow instability are explored.•Increase in SPL and decrease in frequency can enhance heat transfer.•Sound power efficiency increases with the decrease in sound frequency.