Practical aspects of modal propagation through water filled pipes

The use of ultrasound for sensing and communication is growing. Many measurement applications (such as flow metering and level sensing) involve the use of guided acoustic energy, for example constrained within a liquid filled pipe. This paper discusses the problem of axisymmetric sound propagation in pipes, with particular reference to ultrasound, and extends the theory to allow prediction of the amplitudes of propagating modes for a given source, receiver and pipe geometry. An experimental confirmation of the theory has also been obtained and is described.