Numerical Study on the Interaction of an Inextensible Filament in a Uniform Fluid Flow Using the Immersed Boundary Method

Abstract

Numerical modeling of fluid-structure interaction problems are challenging in the field of computational fluid dynamics because of the complex geometries involved and freely moving boundaries. Flapping of an inextensible filament in a uniform fluid flow is such a problem which mimics the swimming of energy harvesting eel fish. Recently, immersed boundary method has found much attention in simulating fluid-structure interaction problems due to its easiness in grid generation and memory and CPU savings. In the present work, we employed an improved version of immersed boundary method proposed by Shin et al. [1] which combines the feedback forcing scheme of the virtual boundary method with Peskin’s regularized delta function approach. A FORTRAN code is developed for the simulation of flexible filament flapping in a uniform fluid flow. The code is validated for the bench mark problem of two-dimensional flow over a circular cylinder. A single filament hanging under gravitational force is simulated using the developed code which is analogous to a rope pendulum and the results are compared with available analytical results. The results are found to be in good agreement. Finally, the interaction of the flapping filament in the uniform fluid flow is studied for different flow and structure parameters. The production of a series of vortex procession obtained in the case of flapping of filament is in good agreement with the previous available experimental and numerical results.