It has long been recognized that the oscillation of a fluid in a conduit can lead to an increase in the rate of axial mass transport.
Recently it was proposed using fluid oscillations to increase the mass transport and selectivity of supported liquid membranes. The quadratic dependence of the enhancement in transport on tidal oscillalions suggested that the resistance to mass transport of the interior of the membrane could be eliminated, the transport ultimately being limited by the end regions. In this paper we present the results of numerical simulations of osciHatory mass transport in a finite length slug in a circular tube which show that the influence of the end regions on the degree of transport enhancement is always of the order of the slug aspect ratio. End effects are thus negligible provided the aspect ratio is small (as would be expected for a supported liquid membrane), and hence a membrane can be designed whose effective thickness is much less than a pore radius. These results are qualitatively confirmed by experiments with a model liquid membrane system in which an effective thickness of l/6 of a pore diameter was achieved.