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Experiments in Fluids

, 54:1492 | Cite as

Flow control for aero-optics application

  • B. Vukasinovic
  • A. Glezer
  • S. Gordeyev
  • E. Jumper
  • W. W. Bower
Research Article
Part of the following topical collections:
  1. Topics in Flow Control

Abstract

The mitigation of aero-optical aberrations in the wake of a surface-mounted turret comprised of a hemisphere mounted on a matching cylindrical support is investigated in wind tunnel experiments. The effects of hybrid (passive/active) flow control on the aero-optical and aerodynamic characteristics of the flow over a conformal optical aperture embedded in the hemispherical cap are investigated at M = 0.3 and Re D = 4.46 × 106. Direct optical diagnostics of 2D wavefronts over the aperture is performed using a high-speed Shack-Hartmann wavefront sensor for a range of aperture orientations on and off the streamwise center plane. Aerodynamic flow diagnostics includes arrays of static and dynamic pressure ports on the turret and the ground plane that help characterize flow separation and the wake topology. The global flow is passively controlled by a forward-facing partition plate that increases the flow receptivity to and the effectiveness of arrays of high-frequency fluidic oscillating jets that are placed upstream of the aperture. It is shown that the hybrid flow control yields significant improvements in the aero-optical characteristics of the flow over the aperture that exceeds the individual effects of passive and active control.

Keywords

Elevation Angle Optical Aberration Active Flow Control Wavefront Sensor Baseline Flow 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

Aj

Exit area of the actuator orifice

Ao

Frontal turret area

Cp

Pressure coefficient

Cμ

Mass flow rate coefficient

D

Turret diameter

f

Frequency

M

Freestream Mach number

OPD

Optical path difference

OPDrms

Spatial root-mean-square of OPD

R

Turret radius

RA

Optical aperture radius

ReD

Reynolds number

StD

Strouhal number

U0

Freestream velocity

Uj

Average jet velocity

H

Height of turret base

α

Elevation angle of optical aperture

β

Azimuthal angle of optical aperture

δ

Boundary layer thickness

γ

Local azimuth angle of pressure ports

ρ

Air density

ρSL

Sea-level air density

Notes

Acknowledgments

This work has been supported by the Air Force Research Laboratory, Air Vehicle Directorate, WPAFB, OH and the Boeing Company. Support by the AFRL program manager Donnie Saunders and SARL-tunnel personnel is greatly appreciated.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • B. Vukasinovic
    • 1
  • A. Glezer
    • 1
  • S. Gordeyev
    • 2
  • E. Jumper
    • 2
  • W. W. Bower
    • 3
  1. 1.Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaUSA
  2. 2.Department of Aerospace and Mechanical EngineeringUniversity of Notre DameNotre DameUSA
  3. 3.The Boeing CompanySaint LouisUSA

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