Educational uses of a microflown p-u probe

Abstract

Two of the most useful transducers I have ever purchased for my research lab are a B&K Type 8001 mechanical impedance head and a Microflown p-u matchstick probe acoustic impedance head. This talk will illustrate several educational demonstrations one can perform using a Microflown p-u probe. One demonstration will show the transition from the near-field of a spherical source (where pressure and velocity are in quadrature) to the far-field (where pressure and velocity are in phase). Another demonstration will illustrate the relative phase differences for pressure and velocity upon reflection from an open or closed end of a pipe. A third demonstration will show how a measurement of acoustic impedance can be used to determine the undamped natural frequency of a Helmholtz resonator, which in turn may be used to accurately predict the length correction at the open end of the resonator mouth. Additional demonstrations may be shown if time permits.