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Influence of nucleation on cavitation inception in tip leakage flows
journal contribution
posted on 2023-05-21, 16:04 authored by Patrick RussellPatrick Russell, Luka BarbacaLuka Barbaca, James VenningJames Venning, Bryce PearceBryce Pearce, Paul BrandnerPaul BrandnerCavitation in a tip leakage flow is experimentally investigated in a cavitation tunnel using a stationary hydrofoil analogy. The experiments were performed for different tip clearances (𝜏=gap height/maximum profile thickness ) and hydrofoil incidences (α). The chord-based Reynolds number remained fixed at 𝑅𝑒=3×106 . The influence of nucleation on both inception and developed cavitation is evaluated by performing tests with two populations of freestream nuclei: a low concentration with strong critical tensions for activation and a high concentration with weak critical tensions. These populations represent the extremes that would be expected in practical tip leakage flows. Cavitation was characterized using high-speed imaging and acoustic measurements. Following a survey of developed cavitation topology for a range τ and α values, 𝛼=6° was selected for further investigation of cavitation inception as it demonstrated a rich variety of physical processes. From the acoustic measurements, the worst performance in terms of cavitation inception was observed at an intermediate gap height of around 𝜏=0.6–0.8 for the “strong water” case. Broadly, cavitation and inception is intermittent when nuclei are sparse, becoming continuous as additional nuclei are introduced. While a continuous cavity in the seeded flow resulted in a higher baseline acoustic signature, sparse populations allow the leakage vortex to sustain tension, which can result in extremely loud incipient events. Optimization of gap height will, therefore, depend on the expected nuclei population during operation.
Funding
Defence Science and Technology Group
History
Publication title
Physics of FluidsVolume
35Article number
013341Number
013341Pagination
1-15ISSN
1070-6631Department/School
Australian Maritime CollegePublisher
Amer Inst PhysicsPlace of publication
Circulation & Fulfillment Div, 2 Huntington Quadrangle, Ste 1 N O 1, Melville, USA, Ny, 11747-4501Rights statement
© 2023 Author(s). Published under an exclusive license by AIP Publishing.Repository Status
- Restricted