CONTINUOUS-WAVE METHODS APPLIED IN DETERMINING THE VELOCITY OF FAST ULTRASONIC-WAVES IN SATURATED POROUS-MEDIA

The application of measuring methods with continuous waves for study o f the propagation velocity of fast ultrasonic waves in a liquid-satura ted porous material is considered. The technique has recourse to (i) d etection of the amplitude of interfered waves and (ii) detection of th e phase of the transmitted wave, while the frequency varies linearly w ith time and the thickness of porous samples is constant. The two proc edures permit convenient determination of the presence of dispersion a nd the velocity of the dispersionless waves. Relatively large amplitud es of excited continuous waves and high degree of accuracy of the meth ods recommend them as useful tools for study of dynamic properties of saturated porous materials.