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Session MB - Drops I. Emulsions & Drops.
MIXED session, Tuesday afternoon, November 23
Grand II, Westin Seattle

[MB.005] Simulation of Drop Dynamics in Complex Fluid: Shear-induced Deformation

Pengtao Yue, James J. Feng (Department of Chemical and Biological Engineering and Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada), Chun Liu (, Department of Mathematics, The Pennsylvania State University, University Park, PA 16802, USA), Jie Shen (Department of Mathematics, Purdue University, West Lafayette, IN 47907, USA)

This talk reports our recent simulations of drop deformation in steady and startup shear flows. At least one of the components is viscoelastic. The steady deformation depends on the viscoelasticity of the components in a complex way. If the drop phase is viscoelastic, then drop deformation decreases with increasing Deborah number. If the matrix is viscoelastic, however, the drop deformation decreases with De for small De, but increases with De for larger De. This reconciles conflicting experimental reports in the literature. In shear startup, drop deformation undergoes an overshoot and undershoot scenario, consistent with experimental observations. By analyzing the flow and nonlinear stress fields at the interface, we explain the above results by the rheology of the fluids.

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