AbstractA study on the effects of flow pulsations on interphase mass or heat transfer has been made. The situation corresponds to fully developed flow in a long conduit with a periodic pressure gradient at amplitudes which cause flow pulsations without flow reversal. It is shown that the basic three‐parameter formulation can be reduced to a one‐parameter problem in the boundary layer formulation. Solutions are developed over wide ranges of the parameters in both the basic and the boundary layer formulations.The boundary approach gives accurate results over wide ranges of the parameters. Pulsations cause increases in the time‐averaged interphase flux at intermediate values of a composite frequency‐space variable. However, at small values of this variable the pulsations cause a decrease in the flux such that the overall space‐averaged flux is always decreased.