Effect of the Leading-Edge Extension (LEX) Fence on the Vortex Structure over the F/A-18.

Abstract

The effects of the Leading Edge Extension (LEX) fence on the vortex structure over the F/A-18 at moderate to high angles of attack were studied using a 1/9 scale wind tunnel model and a 1/48 scale water tunnel model. Measurements at the tip of one of the vertical fins of the wind tunnel model confirmed that the fence reduced fin vibration caused by vortex breakdown. Flow visualisation in the water tunnel and in the wind tunnel showed that the fence caused the formation of a second LEX vortex, of the same sense as the main LEX vortex, but originating on the LEX leading edge outboard of the fence. Visualisation of the surface flow around the fence showed in detail how the fence caused the second LEX vortex. The effects on vortex breakdown and fin vibration of the interaction between the main and second LEX vortices are discussed.

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Document Details

Document Type
Technical Report
Publication Date
Feb 01, 1997
Accession Number
ADA324125

Entities

People

  • D. H. Thompson

Organizations

  • Defence Science and Technology Group

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Aerodynamic Characteristics
  • Aircrafts
  • Cameras
  • Engineering
  • Flow
  • Flow Visualization
  • Geometry
  • High Angles
  • Horizontal Stabilizers
  • Leading Edge Flaps
  • Leading Edges
  • Materials Science
  • Measurement
  • Test Facilities
  • Water Tunnels
  • Wind Tunnel Models
  • Wind Tunnels

Fields of Study

  • Physics

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