sage action, inc.
  Airflow Visualization and Measurement
 
 
   
  Two Applications where the SAI Bubble Generator was used in studying Aircraft Aerodynamics -
   
  THE SPACE SHUTTLE & JET AIRCRAFT
   
  THE SPACE SHUTTLE
 
Wind tunnel test on a 1:20th scale model of the Space Shuttle. Note the turbulent airflow behind the engines of the Shuttle. Understanding this flow pattern led to the development of the tailcone that was placed over the engines to reduce the effect of the turbulence on the tail control surfaces of the 747 while the two were attached.
 
   
 
  Photo Credit - NASA
   
 
 
  JET AIRCRAFT - Effect of a close-coupled canard on a swept wing
 

ABSTRACT From SAI Research Report - 7501

Many current aircraft designs for future air-superiority fighters incorporate close-coupled canards. This relatively new configuration has been developed, principally, through wind tunnel testing that indicates a favorable aerodynamic interaction between the canard and wing at high incidence. The favorable interaction creates a high total lift capability and reduced trimmed drag, leading to important gains in combat effectiveness. The investigation here is directed at obtaining a physical understanding of the canard/wing flowfield and then building from it an analysis of the aerodynamic interaction. Wind tunnel tests were carried out on a representative configuration in the NASA Langley Research Wind Tunnel. Visualization of details of the flow patterns, such as leading-edge vortices, vortex breakdown and separation, was achieved by using small, neutrally-buoyant bubbles as flow tracers and a surface oil flow technique. Typical photographs are presented, together with a composite sketch of the significant features of the flowfield above the wing. Based upon these results, a simplified theoretical model is formulated and an iterative solution is outlined.
 
  Overall Test Setup Of The Close-Coupled Canard Model In NASA Langley V/STOL Research Wind Tunnel
   
 
  Flow patterns without the Canard at angle of attack of 10 °, shows flow over the upper surface of the wing.
   
 
  Flow patterns without the Canard at angle of attack of 25°, shows flow over the upper surface of the wing.
   
 
  Close-Coupled Canard installed at angle of attack of 25°
   
 
  Expanded view Close-Coupled Canard installed at angle of attack of 25°
   
 
  Top view of Close-Coupled Canard installed at angle of attack of 25°
   
 
  Compostie Sketch Of Significant Features Of The Close-Coupled Canard
   

 

 
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