Investigation of acoustically-coupled shear layers using particle image
velocimetry. Quantitative visualization of
acoustically-coupled shear layers that are formed due to fully turbulent inflow
past a coaxial side branch resonator mounted in a duct is performed using a
technique of digital particle image velocimetry. Imaging of the flow structure
conducted in conjunction with unsteady pressure measurements leads to patterns
of velocity, vorticity, and streamline topology at various phases of the
acoustic cycle. Global instantaneous images, as well as time-averaged images,
are evaluated to provide insight into the flow physics during tone generation.
In particular, the effect of the interaction between two shear layers that form
across the coaxial side branches on the acoustic power generation is studied for
various resonator geometries.
P. Oshkai and T. Yan.