Ultrasonic nonspecular reflectivity near longitudinal critical angle

The intensity profile of an ultrasonic beam reflected from a liquid‐solid interface is determined by a numerical integration method. This numerical approach takes into account the influence of absorption in the media and is valid for all angles of incidence. The reflected profile is calculated for a specific case: incidence near the longitudinal critical angle for a water‐Plexiglas interface. The calculated results demonstrate the existence of nonspecular reflectivity near this particular critical angle and provide a quantitative description of its basic features. Theoretical results and experimental measurements are compared. [Work supported by the Office of Naval Research, U.S. Navy.]