Study of the Transition to Turbulence Within a Curved Rectangular Channel With 40 to 1 Aspect Ratio

Abstract

Longitudinal turbulence intensity and streamwise mean velocity variations are studied from measurements using single-sensor hot-wire probes at Dean numbers from 50 to about 450 in a curved rectangular channel with 40 to 1 aspect ratio, mild curvature, and an inner to outer radius ratio of 0.979. Measured results show significant increases in the longitudinal turbulence intensity as the Dean number increases above 150. These increases are first apparent near the concave surface in upwash regions between individual vortices which make up each vortex pair. Such increases correspond closely with twisting vortex motions, which is important in regard to transition from laminar to turbulent flow because these variations provide evidence that twisting results in the first important increases in turbulence energy at a given location as the Dean number increases.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1991
Accession Number
ADA246314

Entities

People

  • Steven J. Fuqua

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Energy and Power Technologies
  • Sensors

DTIC Thesaurus Topics

  • Aspect Ratio
  • Boundary Layer
  • Flow
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Mechanics
  • Geometric Forms
  • Geometry
  • Hot Wire
  • Measurement
  • Mechanical Engineering
  • Mechanics
  • Poiseuille Flow
  • Test Facilities
  • Three Dimensional
  • Turbines
  • Turbulent Flow

Fields of Study

  • Physics

Readers

  • Fluid Mechanics and Fluid Dynamics.