An improved water-filled impedance tube.
A water-filled impedance tube capable of improved measurement accuracy and precision is reported. The measurement instrument employs a variation of the standardized two-sensor transfer function technique. Performance improvements were achieved through minimization of elastic waveguide effects and through the use of sound-hard wall-mounted acoustic pressure sensors. Acoustic propagation inside the water-filled impedance tube was found to be well described by a plane wave model, which is a necessary condition for the technique. Measurements of the impedance of a pressure-release terminated transmission line, and the reflection coefficient from a water/air interface, were used to verify the system.
Wilson
Preston S
PS
Department of Aerospace and Mechanical Engineering, Boston University, 110 Cummington Street, Room 101, Boston, Massachusetts 02215, USA. psw@bu.edu
Roy
Ronald A
RA
Carey
William M
WM