Effects of Jet-Interaction on Pitch Control of a Launch Abort Vehicle

Michael Aftosmis, Stuart Rogers
2008 46th AIAA Aerospace Sciences Meeting and Exhibit   unpublished
This work describes a series of high-fidelity computational studies examining the control authority of Attitude Control Motors (ACMs) for pitch control of an early candidate design of the Orion Launch Abort Vehicle (LAV). This study included both unsteady Reynolds-Averaged Navier-Stokes (RANS) and both steady and unsteady inviscid simulations. Over 50 overset RANS and 650 Cartesian Euler simulations were performed to characterize the aerodynamics of an early design for the Orion Pad-Abort LAV.
more » ... hese simulations spanned low-subsonic to high supersonic flight conditions and considered angle-of-attack variations from -30°to 50° and sideslip angles of 0° and 30°. Investigations of Jet Interaction (JI) showed that adverse JI occurs at positive angles-of-attack when the ACM jets screen the LAV tower from the oncoming flow. In particular, adverse JI causes ACM authority to drop dramatically at positive α over Mach numbers from 0.7-1.6, and can result in control reversal for some flight conditions. We briefly describe subsequent design modifications that can markedly improve control authority.
doi:10.2514/6.2008-1281 fatcat:lykos7ivsfeylpofm42hc7rnji