USA flag logo/image

An Official Website of the United States Government

Mitigation of Aero-Optic Distortions by Active Flow Control

Award Information

Department of Defense
Air Force
Award ID:
Program Year/Program:
2002 / STTR
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
Combustion Research and Flow Technology, Inc.
6210 Kellers Church Road Pipersville, PA -
View profile »
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Phase 1
Fiscal Year: 2002
Title: Mitigation of Aero-Optic Distortions by Active Flow Control
Agency / Branch: DOD / USAF
Contract: F49620-02-C-0059
Award Amount: $99,955.00


"Laser beam interactions with free shear turbulent structures in the context of a recessed cavity window will be investigated. The proposed program will investigate the aero-optic degradation of a laser beam, housed within the cavity, and its remediationusing high frequency flow control. Beam wander and displacement statistics, obtained via a Position Sensitive Detector (PSD), will be complemented by non-intrusive flowfield measurements using Particle Image Velocimetry (PIV), Laser Speckle for densityfluctuations, Schlieren, etc. Using a previously generated very high-resolution database of high quality, temporal Large Eddy Simulation data, turbulent length-scales, phase-velocity, turbulent kinetic energy spectrum, cross-correlations, etc. will beextracted for the cavity shear layer. Mechanisms underlying effectiveness of high frequency control will be identified and correlated with growth of vortical, large-scale structures. Analytical predictions of beam displacement will be performed andcompared with measurements. A Low Dimensional Model, based on Proper Orthogonal Decomposition (POD), will be used to examine alternate time-dependent strategies for control of turbulent structures in the cavity flowfield. Ascertaining the ability of flowcontrol to manipulate laser/turbulence interactions, thereby reducing the demand upon any adaptive-optics system, is the underlying goal of the proposed STTR effort. The proposed STTR research will lead to a high frequency actuator design concept, whichcan be directly transitioned to the JSF& UCAV programs. Beyond DE weapons, the flow control technology for reduction of optical degradation by turbulence is of great relevance for reduction of bore-sight-error (BSE) for a tracking system or blurelimination for an imaging system. From the perspective of flow control, the high frequency actuator is closely related to current research in aircraft exhaust noise reduction, exhaust plume infra-red (IR) signature control and weapons bay dynamic loadattenuation."

Principal Investigator:

Neeraj Sinha
Vice President & Technical Director

Business Contact:

Neeraj Sinha
Vice President & Technical Director
Small Business Information at Submission:

Combustion Research & Flow Technology, Inc.
174 North Main Street, P.O. Box 1150 Dublin, PA 18917

EIN/Tax ID: 232759059
Number of Employees:
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Research Institution Information:
U.Miss/Nat'L Cntr. For Phys. Acoust
1 Coliseum Drive
University, MS 38677
Contact: John M. Seiner
Contact Phone: (662) 915-5630
RI Type: Nonprofit college or university