Low Reynolds number pumping near an elastic half space

Oscillatory flow near deformable boundaries arises in a variety of biological and engineered contexts. In this study, peristaltically driven flow is quantified as a function of a passive boundary's elasticity for transverse and longitudinal driving waves. Compliance of the elastic half-space generally leads to a decrease in flow rate. However, under longitudinal loading and sufficient confinement, flow can increase. Lagrangian velocities quantify reflux, supporting claims longitudinal waves reduce reflux near the peristaltic wave. We show our analysis agrees with experimental data for pulsatile cerebrospinal fluid flow in the brain.