Cavitation Inception for Non-elliptically Loaded Fins

Open Access
Author:
Hanson, David Royal
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 30, 2012
Committee Members:
  • Eric Paterson, Thesis Advisor
Keywords:
  • Cavitation
  • Vortex Lattice Theory
  • Tip Vortex Cavitation
  • Particle Image Velocimetry
  • Acoustic Measurements
Abstract:
Cavitation on lift-producing fins often occurs at higher cavitation numbers in the tip vortex than elsewhere in the flow. Tip vortex cavitation inception is known to depend on the flow Reynolds number and the lift produced. This investigation explored the effect of variation of the spanwise distribution of lift on cavitation in the tip vortex. A series of three fins with identical lift but different spanwise lift distributions (elliptical, tip-loaded, and root-loaded) was designed and tested in the 12-inch-diameter water tunnel at the Garfield Thomas Water Tunnel facility at The Pennsylvania State University. Visual and acoustic cavitation desinence calls were made over a range of angles of attack; force measurements were taken and the flow near the fins was measured with Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). The tip-loaded fin tended to show the least favorable tip vortex cavitation inception behavior; the root-loaded fin showed the most favorable behavior, and the elliptically-loaded fin was between these extremes.