Numerical study of an inextensible, finite swimmer in Stokesian viscoelastic flow

作者：Salazar Daniel^*; Roma Alexandre M; Ceniceros Hector D

来源：Physics of Fluids, 2016, 28(6): 063101.

DOI：10.1063/1.4953376

A numerical investigation of an Immersed Boundary (IB) model of an effectively inextensible, finite swimmer in a Stokesian Oldroyd-B flow is presented. The swimmer model is a two-dimensional sheet of finite extent and its gait is generated by an elastic force which penalizes deviations from a target shape. A non-stiff IB method is employed to remove the impeding time step limitation induced by strong tangential forces on the swimmer. It is found that for a swimmer with a prescribed gait its mean propulsion speed decreases with increasing Deborah number De toward an apparent asymptotic minimal value. However, as the swimmer is allowed to deviate more from the target shape, the monotonic locomotion behavior with De is broken. For a sufficiently flexible swimmer, viscoelasticity can enhance locomotion but the swimmer in the viscoelastic fluid always remains slower than when it is propelling in a Newtonian fluid. Remarkably, the addition of viscoelastic stress diffusion dramatically alters the swimmer propulsion and can lead to a speed-up over the swimmer in the Newtonian fluid. Published by AIP Publishing.

• 出版日期2016-6