Numerical Simulation of the propulsion of oscillating bodies

In nature, microswimmers present different propulsion strategies due to their need to move and survive. This has been previously studied in rigid geometries at low Reynolds number flow. The goal of this investigation is to analyze both the viscous shear stresses on the surface of deformable bodies and the vorticity field to determine if the oscillating body is able to have propulsion. In this study, the propulsion of two-dimensional geometries that continuously change, as a function of time, from a circle shape to an ellipsoidal configuration, is investigated. The oscillating body is immersed on a low Reynolds number flow. The dimensionless two-dimensional incompressible Navier–Stokes equations are solved by the Spectral Element Method with moving meshes. The governing parameters of the system are the Reynolds number, and the non-dimensional frequency and amplitude of the motion. The Reynolds number based on the inlet velocity of the flow and the diameter of the circle varies between 20 and 200, while the amplitude of the deformation is in the range from 0.3 to 0.7 and the frequency is set to 1. A two-dimensional map is generated, in which the Reynolds number and the amplitude are involved. The map shows the influence of the flow patterns on the propulsion force of the body.