Suspension plug in an oscillatory pipe flow: simulations

Transport phenomena in neutrally buoyant dense particle suspensions subject to shear depend strongly on the applied strain amplitude (related to the distance travelled by particles in one oscillation divided by the characteristic lengthscale) at vanishingly low Reynolds numbers. However, the evolution of these particle-fluid interactions at low, but finite Reynolds numbers and its dependence on both the strain amplitude and the number of oscillations is currently less understood. We use particle-resolved Direct Numerical Simulations (pr-DNS) to investigate the movement of a particle plug subject to pressure-driven oscillatory Poiseuille flow inside a plane channel. Simulations are carried out at Reynolds numbers O(1-10), and the effects of weak inertia on particle dynamics are explored. Understanding particle suspension behavior at finite Reynolds numbers could inform experimental and industrial applications of such flows.