Effects of pulsating flow on convective heat transfer in two-dimensional sinusoidal wavy passages are investigated numerically. A straight channel and three channels with wavy walls are considered. Phase shifts (? = 0°, 90°, and 180°) between the bott om and the top walls are studied for the wavy channels. The phase angle between walls is adjusted by shifting the lower wall while the upper wall is kept stationary. The unsteady, two-dimensional form of the Navier-Stokes and the energy equations are utilized and numerically solved by a SIMPLE algorithm. The dimensionless oscillating frequency (Womersley number) is studied within the range of 10 ? ? ? 30. Two different pulsating amplitudes of A = 0.25 and A = 0.75 are considered for a fluid with the Prandtl number of 7.0 and Reynolds number of 100. The channel geometry, pulsating frequency, and amplitude significantly affect the flow patt ern and the temperature distribution in the channel. The results obtained demonstrate that pulsating flow in wavy channels has strong effects on convective heat transfer while has no influence in straight channels. © 2020 by Begell House, Inc.