Qualitative and Quantitative Study of the Flow Physics in the Vicinity of an Oscillating Plate in Viscous Fluids

In this paper, we report on a comprehensive experimental study on the fluid-structure interactions of a submerged rigid plate undergoing harmonic oscillations in a quiescent, Newtonian, viscous fluid. We conduct a detailed qualitative and quantitative analysis of the problem for broad ranges of oscillation parameters, including frequency and amplitude, to highlight the fluid-structure interaction mechanisms responsible for the hydrodynamic forces acting on the plate. The primary objective of this study is to understand the effect of the oscillation parameters on the resulting qualitative flow patterns and analyze their relation with vortex shedding and hydrodynamic forces. We classify different flow regimes depending on the behavior of the flow in the vicinity of the structure, with particular focus on vortex shedding and symmetry breaking phenomena, and analyze the forces in each regime by using particle image velocimetry and direct force measurement via a load cell. Comparison of the obtained experimental results against values predicted from numerical and semi-analytical models shows good agreement between our approach and the literature. Fundamental findings from this work have direct relevance to various engineering applications, including energy harvesting devices, biomimetic robotic system, and micro-mechanical sensors and actuators.