Acoustic pulse diagnostics of relaxation media

Abstract

The investigation of propagation of acoustic fields in different media is an important source of information about nonideal properties of these media. For study of small-amplitude acoustic waves, the most essential of the nonideal properties are the dissipative–dispersive properties, which are characterized by the frequency dependence of the absorption factor and the phase velocity. These properties can be described in terms of relaxation processes, which arise in the field of acoustic waves. Conventional ways to determine the relaxation times spectrum (RTS) parameters are acoustic spectroscopic measurements of temperature–frequency dependence of absorption and phase velocity of sound in the medium. Currently, such problems can be solved by applying the pulse methods of measurements. In the report the possibilities of acoustic pulse diagnostics of relaxation media are discussed. Parameters of media (such as five moments of RTS) are defined which can be determined experimentally by methods of pulse acoustic diagnostics. The criteria for a pulse excitation source and its registration distances are obtained which provide the most efficient pulse acoustic diagnostics. The comparison of developed approach with the first experiments is fulfilled.