Acoustically probed Taylor-Couette flow apparatus

Abstract

A Taylor-Couette cell for the investigation of geometrical phase in acoustics has been constructed. The inner and outer cylinders are made of acrylic. the cell has an inner cylinder radius of 9.477 cm, radius ratio of 0.902, and cavity aspect ratio of 49.2. Two high performance d.c. motors can rotate the cylinders independently. the angular speed of the cylinders is monitored by a photo-interrupter. A piezoelectric polymer (PVDF) transducer mounted on the inner cylinder drives the acoustic field in the cavity and a 6.02 mm diameter electret microphone embedded in the wall of the inner cylinder acts as a receiver. Static measurements of the acoustic modes in the annular cavity show good agreement with theory, though measurements at different angular locations of the transducer reveal 2% nonuniformities. The effects of nonuniformities could be overcome by rotating the cylinders at high speeds. the performance under these preliminary tests indicate that an apparatus of this design is suitable for investigations of acoustics in rotating flows.