Experimental investigation of the effects of cavitation control on the dynamics of cavitating flows around a circular cylinder

Abstract

In this work, we experimentally investigated effects of cavitation control on cavitating flows around a circular cylinder using mesoscale surface structuring. We considered two kinds of scalloped riblets, machined on the surface of a cylinder, to control cavitation. First, we tested a smooth cylinder placed in a cavitation tunnel at various cavitation numbers and Reynolds numbers. Then, we tested a cylinder with horizontal riblets and a cylinder with vertical riblets under the same conditions. We analyzed the effects of these scalloped riblets on cavitation dynamics behind the cylinder and on the cavitation-induced vibration. A high-speed camera captured the cavity structures behind the cylinders, and a load cell measured the associated pulsating lift force. Results showed that the riblets reduced the amplitude of a cylinder’s cavitation-induced vibration significantly compared to the amplitude of a smooth cylinder. In addition, the riblets mitigated tip-vortex cavitation and cavity structures in most cavitating regimes. At Reynolds numbers 1.0×105 and 1.5×105 and cavitation number 1.0, the vibration was decreased up to 60% for the cylinder with horizontal riblets.