Ventilated cavities detaching from a backward facing step are investigated for a range of upstream boundary layer thicknesses in a cavitation tunnel. The upstream turbulent boundary layer thickness is varied by artificial thickening of the test section natural boundary layer using an array of transversely injected jets. Momentum thickness Reynolds numbers from 8.5 to 28×103 were tested giving boundary layer thickness to step height ratios from 1.25 to 3.8. A range of cavitation numbers (based on the cavity pressure) were obtained by variation of the ventilation flow rate for fixed freestream Reynolds and cavitation numbers. Cavity length to step height ratios from 15 to 60 were achieved. Cavity length was found to be linearly dependent on ventilation rate and to decrease with increasing boundary layer thickness. This result may have implications in the practical optimization of these flows which occur in applications such as drag reduction on marine hull forms.
History
Publication title
The Proceedings of the 19th Australasian Fluid Mechanics Conference
Editors
H Chowdhury & F Alam
Pagination
1-4
ISBN
978-0-646-59695-2
Department/School
Australian Maritime College
Publisher
RMIT University
Place of publication
Melbourne, Australia
Event title
19th Australasian Fluid Mechanics Conference
Event Venue
Melbourne, Australia
Date of Event (Start Date)
2014-12-08
Date of Event (End Date)
2014-12-11
Rights statement
Copyright 2014 Australasian Fluids Mechanics Society