A Preliminary Investigation of Jet Thrust Vectoring with Plasma Actuators
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Date
2024-05
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The Ohio State University
Abstract
A preliminary investigation of jet thrust vectoring through the attachment of flow to a curved “reaction surface” in a round subsonic jet using plasma actuators is conducted. Plasma actuator thrust vectoring, though thus far unproven, is a promising technique for its low power input and potentially rapid response compared with mechanical and fluidic thrust vectoring configurations. The proposed methodology utilizes an array of plasma actuators, distributed evenly around the azimuth of a jet, opening to a curved nozzle extension (i.e. reaction surface), in which pressure taps are embedded. Azimuthal pressure profiles are collected across a range of actuation frequencies to examine the capacity for plasma actuators to generate asymmetric suction on the reaction surface (indicating vectoring of the thrust). Plasma actuators are expected to asymmetrically manipulate the shear layer behavior through thermal perturbation of the natural jet shear layer instability (i.e., the Kelvin-Helmholtz instability) which controls shear layer roll-up and vortex merging behavior—important factors in vortex entrainment capabilities. This is expected to alter the azimuthal location of jet attachment and detachment to/from the reaction surface, and thus the direction of deflection as flow travels along the curved reaction surface, thereby vectoring the thrust.
Relative to an unexcited flow, low excitation frequencies are found to increase suction along the surface downstream of active actuators compared with inactive actuators, while a decrease in suction is found at higher frequencies. Furthermore, at the lowest and highest extremes of the frequency range, impact on suction is reduced, likely caused by a limit in control authority by the low passage rate of vortices and by reduced perturbation amplification by the Kelvin-Helmholtz instability, respectively. The collected data indicates the potential capacity for thrust vectoring, though further diagnostics, such as particle image velocimetry (PIV) and oil-flow visualization, are still required to fully characterize and validate this capacity. Additionally, a further understanding of the impact of nozzle geometry on shear layer behavior is required to optimize this technique.
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Keywords
Shear Layers, Flow Control, Thrust Vectoring, Plasma Actuators