Development of Attached Cavitation at Very Low Reynolds Numbers from Partial to Super-Cavitation

The present study focuses on the inception, the growth, and the potential unsteady dynamics of attached vapor cavities into laminar separation bubbles. A viscous silicon oil has been used in a Venturi geometry to explore the flow for Reynolds numbers ranging from Re=800 to Re=2000. Special care has...

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Bibliographic Details
Published in:Applied sciences 2020-10, Vol.10 (20), p.7350
Main Authors: Ravelet, Florent, Danlos, Amélie, Bakir, Farid, Croci, Kilian, Khelladi, Sofiane, Sarraf, Christophe
Format: Article
Language:English
Subjects:
Aerodynamics
Boundary layer
Cameras
Cavitation
cavitation instabilities
Cavitation number
Cavities
Experiments
Fluid Dynamics
Fluid flow
Holes
Laboratories
laminar cavitation
Laminar flow
Mechanical properties
partial cavitation
Physics
Pressure
Reynolds number
Strouhal number
super-cavitation
Supercavitating flow
Time series
Velocity
Viscosity
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Summary:The present study focuses on the inception, the growth, and the potential unsteady dynamics of attached vapor cavities into laminar separation bubbles. A viscous silicon oil has been used in a Venturi geometry to explore the flow for Reynolds numbers ranging from Re=800 to Re=2000. Special care has been taken to extract the maximum amount of dissolved air. At the lowest Reynolds numbers the cavities are steady and grow regularly with decreasing ambient pressure. A transition takes place between Re=1200 and Re=1400 for which different dynamical regimes are identified: a steady regime for tiny cavities, a periodical regime of attached cavity shrinking characterized by a very small Strouhal number for cavities of intermediate sizes, the bursting of aperiodical cavitational vortices which further lower the pressure, and finally steady super-cavitating sheets observed at the lowest of pressures. The growth of the cavity with the decrease of the cavitation number also becomes steeper. This scenario is then well established and similar for Reynolds numbers between Re=1400 and Re=2000.
ISSN:2076-3417
2076-3417
DOI:10.3390/app10207350