Rapid cavitation in water induced by the reflection of shock waves

Abstract

Negative pressures were produced in distilled water by reflecting shock pulses of 11 MPa off a quasifree water‐Mylar‐air interface. The incident pulses, created by conventional impact techniques, were typically 1.7 μs in duration. An interferometer measured the displacement of the interface from which the velocity history of the Mylar could be extracted. Tension is created in the water when rarefaction waves collide. The tension results in cavitation which is evidenced by a rapid rebound of the Mylar's velocity. Difficulties experienced in previous experiments [P. L. Marston and G. L. Pullen, in Shock Waves in Condensed Matter, 1981, edited by W. J. Nellis et al. (AIP, New York, 1982), pp. 515–519] have been overcome by reducing the thickness of the Mylar which initially constrains the water. Velocity histories give a clear indication of cavitation in the sample; the abrupt tension being relieved by bubble formation within 1 μs. Also evident is reverberation within the spalled layer of the pressure wave radiated by the bubbles. The results suggest an apparent dynamic tensile strength ⩾5 MPa for moderately clean water. [Work supported by ONR and the American Chemical Society Petroleum Research Fund. Marston is an Alfred P. Sloan Research Fellow.]