Numerical simulation of sperm motility under shear flow

Abstract

Sperm motility under fluid flow is of research interest for the efficient design of microfluidic sperm sorter for infertility treatment. Deriving motivation from this, a two-dimensional computational model is constructed using immersed boundary method to study the swimming strategy of sperm like organism under shear flow in a channel. Here, the shear flow is induced by moving the top wall of the channel in the positive direction and bottom wall in the negative direction with equal magnitude of velocity. The fluid flow is modeled using continuity and momentum equations and the governing equations are discretized using finite volume method on a staggered Cartesian grid system. The sperm like organism is modeled as an elastic filament with elastic network of links created using definite number of immersed boundary points. A driving force is applied to the filament which can propel the sperm in the forward direction under no flow condition. But, under applied shear flow, the sperm motion depends on the exact combination of the filament and flow parameters. Through numerical simulations it is found that the initial location of the sperm like organism in the channel greatly decides the final swimming strategy and the swimming speed changes based on this location. It is observed that, organism kept at the center of the channel swims in the forward direction in a centerline fashion, but all other locations the propulsion is different. © 2021 American Institute of Physics Inc.. All rights reserved.