Spectral Characteristics of Sheet/Cloud Cavitation

Abstract

Cavitation observations were made using a highly instrumented 2D NACA 0015 hydrofoil mounted in a specially designed water tunnel. It was found that the dynamic characteristics of the cavitation vary considerably with various combinations of angle of attack and cavitation number, σ. At higher angles of attack, two types of flow unsteadiness are observed. At low σ, a low frequency shedding of cloud cavitation results in a strong oscillation in lift and Δp at a Strouhal number, based on chord length, fc/U, of about 0.15. This frequency is relatively insensitive to changes in σ. As σ is raised, the harmonic content of the oscillations changes significantly. A spectral peak at much higher frequency is noted that increases in frequency almost linearly with cavitation number. Similar behavior is noted in the lift fluctuations. [S0098-2202(00)02503-7]

The transition from sheet to cloud cavitation

“…The cavitation cloud is then carried downstream by the fluid flow and collapses. Lange & Bruin (1997), Kjeldsen, Arndt & Effertz (2000) and Kawanami et al (2002) also made important contributions to the study of this complex phenomenon.…”

Large eddy simulation of unsteady shedding behavior in cavitating flows with time-average validation

“…The time dependent cavitation shedding is more or less found in all the cavitating flows and is particularly obvious in sheet and cloud cavitation. Over the past decades, driven by the knowledge gap, studies on the instability of sheet cavitation and generation mechanism of cloud cavitation have attracted lots of attentions (Kawanami et al, 1997;Delange and Debruin, 1998;Leger and Ceccio, 1998;Kjeldsen et al, 2000;Watanabe et al, 2001;Callenaere et al, 2001;Li et al, 2010). Some previous reviews (Wang et al, 2001;Arndt, 2002;Franc and Michel, 2005) have also outlined the significant progress in the development of experimental measuring or numerical modeling tools to predict the underlying physics of unsteady cavitating flows.…”

Investigation of Two Mechanisms Governing Cloud Cavitation Shedding: Experimental Study and Numerical Highlight

“…Partial cavity shedding phenomenon has been widely investigated in the past decades about different geometries such as hydrofoil profiles [2][3][4][5][6][7] , spheres 8 or Venturi nozzles [9][10][11][12] . As a consequence, a dynamical feature has been clearly consisting of a frothy re-entrant jet reaching back the vapor cavity and eventually cutting it in two, the second "cloud" cavity being advected downstream.…”