Vortex dynamics around a fluctuating beam

Abstract

Fluid Structure Interaction (FSI) analysis for fluctuating beam in viscous fluids has been carried out for the preliminary design of propeller-less underwater drones. The Immersed Boundary Method has been used to address a large variety of Fluid Structure Interaction problems such as insect flight, locomotion of fishes and batoid pieces etc.IB2d is an open-source MATLAB code developed by Battista, which can be used for solving two-dimensional Fluid Structure Interaction problems using the Immersed Boundary Method. The settings of IB2d solver have been verified by reproducing a flapping beam problem. The parameters for this problem have been changed to study the flow generated around a beam tethered at both ends and subjected to a perturbation of the beam in static fluid. The beam has been modelled as a setof Lagrangian points for a given length and stiffness value and the fluid around the beam is modelled as a Eulerian regionof certain viscosity and density. The beam has been perturbed from its equilibrium position by an ellipsoidal arc and the dynamics of vortices around the beams are analyzed both qualitatively and quantitatively. The simulations have been repeated by varying viscosities of the Eulerian region, varying length of the beam and varying stiffness values betweenthe Lagrangian points. The parametric study shows that the magnitude of vorticity around the beam reduces with increasein viscosity and stiffness It is also found that for the same curvature, the motion speed reduces with reduction in the beamlength.