Classical standing-wave analog of the Aharonov-Bohm Effect: Experiment

I will be discussing the experimental investigation into the interaction between a draining bathtub vortex and standing surface waves. Specifically, we examine how the presence of this vortex alters the structure of the standing waves, leading to the formation of distinct patterns that we refer to as "propellers" which radiate outward from the vortex core. The experimental setup involves generating a controlled draining vortex in a water tank and creating standing surface waves using transducers. By varying the parameters of the system, we measure the scattering effects and analyze the resulting wave patterns using high-speed imaging. Theoretical analysis complements these experiments, allowing us to model the interaction between the vortex and the waves, and to predict the conditions under which specific wavefront dislocations—and thus specific numbers of propeller blades—will occur. One of the key findings of our work is that the number of propeller blades—i.e., the arms or radiating spokes of the wavefront pattern—is governed by a dimensionless parameter, denoted as α. This parameter α contains information about the strength of the vortex and the wavelength of the surface waves. By varying α, we are able to control the number of propeller blades and observe different wavefront patterns.