Etude expérimentale de l'influence d'un champ de pression fluctuant sur l'apparition de la cavitation dans un venturi

Effect of a fluctuating pressure field on the behaviour of a cavitation bubble

¹ Laboratoire d'Hydrodynamique de l'Ecole Navale 29240 Brest Naval
² Groupe Phénomènes d'Interface 91120 Palaiseau

Abstract

It is well known that a nucleus subject to a quasi-steady mean pressure drop can either oscillate or asymptotically grow depending the final pressure is above or blow the critical one. Recent investigations have shown that dynamically driven asymptotic growth conditions are associated to sudden mean pressure drops and to small amplitude pressure fluctuations superposed to a mean pressure larger than the quasi-steady critical pressure. In order to provide experimental support to the later results, tests were conducted to determine the effect of the modification of the upstream turbulence on the critical cavitation conditions in a venturi. The results show that cavitation is delayed when turbulence fluctuation intensities increase. A simple analysis associates this effect to the adiabatic behaviour of the gas within the cavity.