TY - EJOU AU - Davidson, Malcolm R. AU - Harvie, Dalton J.E. TI - Viscoelastic Drop Deformation in a Micro-Contraction T2 - Fluid Dynamics \& Materials Processing PY - 2011 VL - 7 IS - 3 SN - 1555-2578 AB - A volume-of-fluid numerical method, adapted by the authors [Harvie, Cooper-White and Davidson (2008)] to simulate the flow of viscoelastic fluids, is used to predict deformation of a viscoelastic droplet carried by an immiscible Newtonian liquid through an axisymmetric microfluidic contraction-expansion. Values of the capillary number and elasticity number are chosen based on corresponding values for a rectangular contraction for which a reentrant cavity at the rear of the drop and subsequent encapsulation behaviour was observed experimentally by Harvie, Cooper-White and Davidson (2008). A reentrant cavity, similar to the observed one, is predicted; however, encapsulation is not achieved. Unexpectedly, a narrow cavity at the centre of the forward face of the drop exiting the contraction is also predicted for low capillary number and high elasticity number. The forward cavity eventually completely penetrates the drop so that it forms a torus. KW - Volume-of-Fluid KW - contraction-expansion KW - microfluidics KW - viscoelastic KW - drop deformation DO - 10.3970/fdmp.2011.007.317