Spatial and temporal characterization of AAOL flight test data

David J. Goorskey; Richard Drye; Matthew R. Whiteley

doi:10.1117/12.922611

15 May 2012 Spatial and temporal characterization of AAOL flight test data

David J. Goorskey, Richard Drye, Matthew R. Whiteley

Proceedings Volume 8395, Acquisition, Tracking, Pointing, and Laser Systems Technologies XXVI; 839509 (2012) https://doi.org/10.1117/12.922611
Event: SPIE Defense, Security, and Sensing, 2012, Baltimore, Maryland, United States

Abstract

This paper discusses spatial-temporal characterizations of recent in- flight Airborne Aero-Optics Laboratory (AAOL) wavefront measurements at transonic speeds (Mach 0.61 - 0.65) with both flat and conformal window turrets as a function of turret look-back angle. Using both proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) analysis methods, the flow dynamics were characterized. The conformal window wavefronts showed shock formation between 85° and 90° that prematurely induced separation at a considerably lower turret look-back angle than would be expected at subsonic speeds without shock. Vortex shedding for the flat window is initiated by the leading edge of the window at a slightly lower angle than the shock-induced conformal window separation. Nevertheless, the vortex shedding dynamics of both flat and conformal window cases were found to be similar. In particular, the vortices grew in width and magnitude with increasing look-back angle. Furthermore, the corresponding shedding frequency dropped with increasing look-back angle maintaining a near constant vortex convection speed equal to about a third of the platform (free-stream) velocity. From these results a new form of the aero-optics frequency scaling relation is proposed that yields a Strouhal number independent of turret look-back angle in the vortex shedding portion of the flow.

Citation Download Citation

David J. Goorskey, Richard Drye, and Matthew R. Whiteley "Spatial and temporal characterization of AAOL flight test data", Proc. SPIE 8395, Acquisition, Tracking, Pointing, and Laser Systems Technologies XXVI, 839509 (15 May 2012); https://doi.org/10.1117/12.922611

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available