LATERAL DISPLACEMENT OF AN ULTRASONIC BEAM UPON REFLECTION FROM A SOLID IMMERSED IN A LIQUID.
TENNESSEE UNIV KNOXVILLE ULTRASONICS LAB
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When an ultrasonic wave of finite cross section is reflected from a liquid-solid interface, a lateral displacement of the reflected beam parallel to the interface results for specific angles of incidence. Adapting the theory for reflection of a longitudinal wave from a liquid-solid interface to account for the finite width of the ultrasonic beam allows one to predict the magnitude of this displacement. A decrease in measured energy ratio reported by previous investigators is caused by the displaced reflected beams partially or totally missing a receiving transducer. Measurement of the energy ratio after tracking the displaced beam leads to results that are in good agreement with theory. An analytic expression for beam displacement is developed for incident angles greater than the critical angle for shear wave generation. Plots of beam displacement over all incident angles are presented from computer data. Experimental measurements are reported for the reflected energy ratio and the beam displacement occurring upon reflection of a longitudinal wave from samples of aluminum and duralumin immersed in water. The amplitude cross section of the reflected beam is mapped out for reflection from beryllium in water. Author