AN EXPERIMENTAL STUDY OF TURBULENCE IN A DRIVEN VORTEX,

Abstract

Measurements have been made at two rotational speeds of the mean motion and turbulence levels within a shallow vortex chamber that has a rotating porous wall as an outer boundary. Very nominal levels of turbulence ( 2 to 3 per cent ) were observed on the central plane of these vortices while a significant portion of the mass flow through the vortex was observed to pass through the end wall boundary layers. A fairly high level of turbulence was then introduced into this vortex chamber by means of a grid of axially aligned bars at the outer rim of the vortex. This high level of turbulence was observed to decay rapidly to a relative level of intensity of about 6 percent, indicating that for tangential Reynolds numbers up to at least 100000, the flow with a driven vortex is stable with respect to the introduction of turbulence. The results obtained corroborate Kendall's findings, namely that the primary cause of the degradation of the performance of a confined vortex is the leakage of mass flux through the boundary layers on the end walls of the vortex chamber. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1964
Accession Number
AD0609460

Entities

People

  • Colman Dup. Donaldson
  • Guy G. Williamson

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Layer
  • Degradation
  • Flow
  • Fluid Mechanics
  • Intensity
  • Layers
  • Mass
  • Mass Flow
  • Measurement
  • Reynolds Number
  • Turbulence

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Atmospheric Science/Meteorology
  • Fluid Dynamics.