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Roll-Yaw control at high angle of attack by forebody tangential blowingThe feasibility of using forebody tangential blowing to control the roll-yaw motion of a wind tunnel model is experimentally demonstrated. An unsteady model of the aerodynamics is developed based on the fundamental physics of the flow. Data from dynamic experiments is used to validate the aerodynamic model. A unique apparatus is designed and built that allows the wind tunnel model two degrees of freedom, roll and yaw. Dynamic experiments conducted at 45 degrees angle of attack reveal the system to be unstable. The natural motion is divergent. The aerodynamic model is incorporated into the equations of motion of the system and used for the design of closed loop control laws that make the system stable. These laws are proven through dynamic experiments in the wind tunnel using blowing as the only actuator. It is shown that asymmetric blowing is a highly non-linear effector that can be linearized by superimposing symmetric blowing. The effects of forebody tangential blowing and roll and yaw angles on the flow structure are determined through flow visualization experiments. The transient response of roll and yaw moments to a step input blowing are determined. Differences on the roll and yaw moment dependence on blowing are explained based on the physics of the phenomena.
Document ID
19960045735
Acquisition Source
Ames Research Center
Document Type
Contractor Report (CR)
Authors
Pedreiro, N.
(Stanford Univ. CA United States)
Rock, S. M.
(Stanford Univ. CA United States)
Celik, Z. Z.
(Stanford Univ. CA United States)
Roberts, L.
(Stanford Univ. CA United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1995
Subject Category
Aircraft Stability And Control
Report/Patent Number
NASA-CR-201844
JIAA-TR-113
NAS 1.26:201844
Accession Number
96N32614
Funding Number(s)
CONTRACT_GRANT: NCC2-55
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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