Keywordsoscillating flow; heat transfer; finned heat exchanger; empirical correlation; heat exchanger; pulse tube refrigerator; shell-tube types; thermoacoustic system; acoustic travelling-wave; porous medium; regenerator hydrodynamic condition; phase angle; flow resistance losses; regenerator; heat transfer; oscillatory flow; time dependent thin film fluid flow; Williamson fluid; oscillating inclined plane; heat transfer and magnetic field; Optimal Homotopy Asymptotic Method (OHAM); thermocapillary; Marangoni number; stability analysis; parallel-plate heat exchanger; standing wave; oscillatory flow; thermoacoustics; regenerator; oscillating flow; pulse tube cryocooler; ineffectiveness; parallel-plate heat exchanger; oscillatory flow; standing wave; thermoacoustic system; turbulence; transition; thermoacoustics; heat exchangers; heat transfer; acoustic power; n/a