An experimental investigation of transient cavitation control on a hydrofoil using hemispherical vortex generators

Abstract

Unsteady cavitation causes noise, damage, and performance decline in the marine engineering and fluid machinery systems. Therefore, finding a method to control the cavitation and its destructive effects is important for the industrial applications. In this work, we proposed a passive method to control the unsteady behavior of transient cavitation at the medium Reynolds number. For this aim, we performed an experimental study using a high-speed camera to analyze the effects of hemispherical vortex generators (VGs) on the cavitation dynamics around a hydrofoil surface. In addition, the pressure pulsations induced by the collapse of the cavity structures in the wake region of the hydrofoil were captured with a pressure transducer mounted on the wall downstream of the hydrofoil. The results showed that the instability behaviors of the cavity structures on the hydrofoil were mitigated using the proposed cavitation passive control method. In addition, the pressure pulsations in the wake region of the hydrofoil were reduced significantly. It can be concluded that the suppression of cavitation instabilities can improve the operating life and reliability of the marine and hydraulic systems.

Experiments on Cavitation Control around a Cylinder Using Biomimetic Riblets

“…Furthermore, they explain the effects of flow vorticity, pressure variation rate, bubble inertia and surface tension effects on the cavity dynamics. Kadivar et al [22,23] investigated the unsteady cavitation dynamics and surge cavitation occurring over both a hydrofoil and a semicircular flat plate. They concluded that the evolution of the sheet cavity to a cloud cavity diverges from the cavity structure dynamics within the cloud cavitating regime.…”

Cavitation suppression and transformation of turbulence structure in the cross flow around a circular cylinder: Surface morphology and wettability effects

“…Hydrodynamic cavitation is often a harmful phenomenon in hydraulic engineering systems and marine applications that usually occurs on propeller blades, ship rudders and moving parts of hydraulic systems. It causes such undesirable effects as material erosion, high vibrational loads, increased noise and overall reduction of hydrodynamic performance (e.g., [54] , [19] , [27] , [51] , [36] , [37] , [56] . It is well known [21] that cavitation is initiated on immersible bodies in the flow regions where pressure locally falls below the one of saturated vapor of the surrounding liquid at a constant temperature, which can, for example, occur because of an increase in the flow velocity, a sudden change in the duct geometry, the passage of an acoustic wave during the half-periods of its expansion (ultrasound cavitation), etc.…”

Experimental Study of the Cavitation Effects on Hydrodynamic Behavior of a Circular Cylinder at Different Cavitation Regimes

“…However, the technique may not provide information on the quantity of vapor within the orifice. Kadivar et al [25,26] studied the effects of the pressure fluctuations in the cavitation surge regime around a two dimensional hydrofoil and a flat plate with semi-circular leading edge. They presented that the cavitation dynamics on the hydrofoil was driven mainly by the re-entrant jet in the cloud cavitation regime.…”