Development of an Experimental Testbed to Study Cavity Flow as a Processing Element for Flow Disturbances
Timothy Vincent, Sidaard Gunasekaran, Michael P. Mongin, Alberto Medina, Alexander M. Pankonien, Philip R. Buskohl · 2024
Sensing and responding to local flow phenomena is a key element in advancing the state-of-the-art in control. As advances in flow sensing and active flow control technology are enabling increased sensor density and more effective flow inputs, novel computing concepts are needed to close the loop on self-contained local flow control systems while minimizing size, weight, and power requirements. Physical Reservoir Computing (PRC) has recently emerged as a promising technique for leveraging the dynamics of a physical system to perform complex signal mapping. For a fluid system, the local flow environment can act as a non-linear operator, mapping disturbances in the flow to a complex non-linear output function, such as a control signal. This process relies on local flow phenomena transforming the disturbances into a higher dimensional space that may be strategically sampled such that a linear combination of the signals forms the desired output. In this work, we build on past computational studies of open-cavity flow by preparing an experimental test bed on which cavity flow PRC may be validated. We employ flow in a water tunnel disturbed by a frequency modulated rotating cylinder with a flap to deliver a sufficiently realistic and complex disturbance to the flow inside a cavity embedded in a plate. We find that the vortex gusts generated by a rotating cylinder with a flap can provide a sufficiently complex signal for PRC within the parameter ranges investigated computationally. We also find that the experimental apparatus is able to collect flow data from the baseline unperturbed flow which is consistent with previous 3D Direct Numerical Simulation (DNS) predictions.