Abstract
In this seminar we will discuss current results of the enhancement of the hydrodynamic damping of gravity waves at the surface of a fluid layer via the interaction with a turbulent vortex flow. Gravity surface waves are excited by oscillating horizontally a square container holding our working fluid (water). At the bottom of the container, four impellers in a quadrupole configuration generate a vortex array at moderate to high Reynolds number, which interact with the wave. We measure the surface fluctuations using different optical nonintrusive methods and the local velocity of the flow. In our experimental range, we show that as we increase the angular velocity of the impellers, the gravity wave amplitude decreases without changing the oscillation frequency or generating transverse modes. This wave dissipation enhancement is contrasted with the increase of the turbulent velocity fluctuations from particle image velocimetry measurements via a turbulent viscosity. To rationalize the damping enhancement a periodically forced shallow water model including viscous terms is presented, which is used to calculate the sloshing wave resonance curve. The enhanced viscous dissipation coefficient is found to scale linearly with the measured turbulent viscosity. Hence, the proposed scheme is a good candidate as an active surface gravity wave dampener via vortex flow reconfiguration. Furthermore, new results on the weakly nonlinear response of the sloshing wave in the presence of the turbulent flow are presented, which display a larger damping enhancement even in the nonlinear regime of the sloshing wave"
About the Speaker
Claudio Falcón got his PhD from Université Paris VI in Paris, France. After a postdoctoral fellowship at the University of Michigan in Ann Arbor, he returned to Santiago, Chile and since 2015 he serves as an Associate Professor at the Physics Department of the Faculty of Mathematical and Physical Sciences of Universidad de Chile. A physicist driven by curiosity and coffee, his research deals with the search for an understanding of patterns and structures using simple experiments that can display interesting physics and simple theory that can describe complex phenomena.
His current research is focused on wave-structure interaction with a strong interest in metamaterials (mechanical, mostly).
Host: Professor Leonardo Chamorro
