VISUALIZATION OF INTERNAL CAUSTICS IN CYLINDRICAL LIQUID CAVITIES WITH A PULSED SCHLIEREN SYSTEM

Visualizations of the acoustic field produced by reflection/refraction of bursts of plane longitudinal waves in the water-filled cylindrical cavity of a solid matrix have been made with a pulsed schlieren syste m. The positions of the cusp points of the caustics formed by successi ve internal reflections in the cavity have been compared with their th eoretical geometrical values. The acoustic field produced by the refle ction of a plane wave on a half-cylindrical mirror has also been studi ed and compared to the field in the vicinity of a caustic, according t o the Pearcey approximation.