Analysis of Propeller Wake Flow Visualization Near a Free Surface

Abstract

Propeller wake flow visualization was carried out for several depths of submergence below a free surface. The wake was visualized by laser light sheet illumination of the blade tip vortex helix seeded with fluorescein dye. Effects of the free surface on the propeller wake were seen at the shallower submergence depths. Instability in the helix was apparent at much shorter distances downstream than has previously been observed in cavitation experiments. The dominant cause of this instability is determined to be caused by the use of inclined universal joints in the propeller drive system. A simple test modification is described for the elimination of this influence. Estimation of Reynolds number, submergence depth, and propeller loading influences on the propeller wake are given. Keywords: Marine propellers wake, Vortex kinematics, Flow visualization.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1988
Accession Number
ADA202674

Entities

People

  • James N. Blanton
  • Scott Fish

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Blade Tips
  • Boundary Layer
  • Drive Shafts
  • Flow Visualization
  • Fluid Dynamics
  • Froude Number
  • Geometry
  • Marine Propellers
  • Measurement
  • Propeller Blades
  • Propellers
  • Reynolds Number
  • Stratified Fluids
  • Turbulence
  • Turbulent Mixing
  • Two Dimensional
  • Universal Joints

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Marine Hydrodynamics

Technology Areas

  • Directed Energy