Viscous effects on the position of cavitation separation from smooth bodies

Abstract

779Flow visualization by the schlieren technique in the neighbourhood of a fully developed cavity on two axisymmetric headforms has shown the existence of laminar boundary-layer separation upstream of cavitation separation, and the distance between the two separations to be strongly dependent on Reynolds number. Based on present results, a semi-empirical method is developed to predict the position of cavitation separation on a smooth body. The method applies only in the Reynolds-number range when the cavitating body possesses laminar boundary-layer separation under non-cavitating conditions. Calculated positions of cavitation separation on a sphere by the method show good agreement with experimentally observed positions.

Numerical simulation of unsteady three-dimensional sheet cavitation

“…Viscous effects are predominant in the detachment of cavitating flow near the leading edge as observed by Arakeri & Acosta [14] and confirmed by Franc & Michel [72] in the case of hydrofoils. They showed that a well-developed cavity always detaches downstream of laminar separation of the boundary layer.…”

Tiny bubbles challenge giant turbines: Three Gorges puzzle

“…The cavitation type triggered through this mechanism could be a foil cavitation such as the one studied by Arakeri [82] and commended by Brennen in [59] ). This gives a span-wise wave length of boundary-layer streaks as l* % 0.479  10 23 m and an estimated spanwise wavelength of GSB as l à GSB % 9:58 mm: Again, this value is roughly equivalent to the observed averaged cavitation streak spacing l à streak % 6:5 mm: Note that the three-dimensional effect disturbed the streak-forming process on both ends of the wing span.…”

Etude synthétique du problème de la modélisation des écoulements partiellement cavitants

“…Heureusement dans ce domaine des progrès substantiels ont été faits ces dernières années [16] sur la base des études effectuées auparavant par ARAKERI [17]. Il semble aujourd'hui établi que la cavité est toujours .…”