Axisymmetric wave propagation in fluid-filled pipes: wavenumber measurements in in vacuo and buried pipes

Detection of water leaks in buried distribution pipes using acoustic methods is common practice in many countries. Correlation techniques are widely used in leak detection, but for these to be effective, the propagation wave speeds and wave attenuation must be known. Relatively predictable for metal pipes, these are largely unknown for the newer plastic pipes, being highly dependent on the pipe wall properties and the surrounding medium. In a previous paper a theoretical model of a buried fluid-filled pipe to predict both wavespeed and attenuation was presented; the aim of the work in this paper is to validate this model experimentally. Wavenumber measurements, encompassing both wavespeed and wave attenuation are made on a water-filled pipe in vacuo and on a buried water-filled pipe. In general, the measurements show good agreement with the theoretical predictions