title: An improved water-filled impedance tube.
abstract: 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.
authors.affiliation: Department of Aerospace and Mechanical Engineering, Boston University, 110 Cummington Street, Room 101, Boston, Massachusetts 02215, USA. psw@bu.edu
authors.forename: Preston S
authors.initials: PS
authors.lastname: Wilson
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Roy
authors.forename: William M
authors.initials: WM
authors.lastname: Carey