Flint O. Thomas

Plasma Flow Control on a Landing Gear Model

This paper reports an effort to extend bluff-body plasma noise control technology demonstrated for a tandem cylinder configuration in [28,29] to a realistic landing gear geometry. Experiments and numerical simulations are presented which focus on plasma flow control of a generalized tandem geometry consisting of the interaction between the hydraulic strut and downstream torque arm of the Gulfstream G550 nose landing gear. Experiments and numerical simulations are preformed at a ReD = 122,000 and M = 0.081. This component work is considered prerequisite to the broader goal of demonstrating plasma noise control on a partially dressed, closed cavity 30% scale model of a Gulfstream G550 nose gear.

Further Experiments on Temporal Proper Orthogonal Decomposition (TPOD) for Closed-Loop Flow Control

Motivated by closed-loop flow control applications, a formulation of the proper orthogonal decomposition (POD) is demonstrated which is capable of characterizing not only the controlled and natural states of a given flow, but also the transient behavior between these states. This approach, which is termed temporal POD (TPOD) extracts the optimum frameof-reference and the temporal information regarding the dynamics of the system in the presence of the flow control. In this paper the TPOD approach is applied to two experiments using active flow control: (1) flow over a circular cylinder at subcritical Reynolds number and (2) flow over a NACA 0015 airfoil at a post-stall angle of attack. Both flows exhibit welldefined and distinct natural and controlled flow states. TPOD is shown to be a very effective tool in characterizing these two states as well as the system trajectories associated with the transient behavior in between.