Velocity Measurements in a 3D Shock Wave Laminar Boundary Layer Interaction. Part 1. Low Speed 2D LDV Measurements.

Abstract

Single component LDV (Laser Doppler Velocimetry) measurements were obtained in the separated 2D thin laminar boundary layer over an elliptic cylinder. The ellipse had an axis ratio of 4:1 and the incoming Reynolds numbers based on the minor axis were 675 and 1350. Velocity measurements were obtained within 0.05 mm from the surface both in attached and reverse flow regions. Painting the model with matt black paint and covering the tunnel walls proved to be effective means of improving signal quality. Measurements were successful both in back and forward scatter modes. The velocity profiles measured with Bragg cells indicate that the flow is separated at the ellipse mid-chord and that the separation bubble extends far downstream in the wake. The velocity profiles in the attached flow region compare well with the results of a boundary layer computation.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 1984
Accession Number
ADA149533

Entities

People

  • G. Degrez
  • J. J. Ginoux

Organizations

  • von Kármán Institute for Fluid Dynamics

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Space

DTIC Thesaurus Topics

  • Acousto-Optic Modulators
  • Boundaries
  • Boundary Layer
  • Computational Science
  • Computations
  • Doppler Effect
  • Flow
  • Flow Fields
  • Fluid Dynamics
  • Laminar Boundary Layer
  • Layers
  • Leading Edges
  • Measurement
  • Reynolds Number
  • Secondary Flow
  • Three Dimensional
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Fluid Dynamics.
  • Fluid Mechanics and Fluid Dynamics.

Technology Areas

  • Directed Energy