Investigation of non-reflecting end conditions within a duct by means of pseudo-random binary pressure pulses

Abstract

A newly developed experimental technique is described for detecting in-duct pressure waves reflected from a termination. An application of the technique to making the end of a partially closed pipe non-reflecting is also described. The method is potentially applicable to a wide range of pressure wave action problems. In cases such as in two-phase flow work it may well be the only practical approach. Measuring times are short, less than one second, and readings are easy to take. The technique adopted is to inject small amplitude pressure pulses in the form of a pseudo-random binary sequence which allows on-line and easily interpreted correlograms of incident and reflected waves to be obtained.