Aerodynamic Flow Control of Wake Dynamics Coupled to a Moving Bluff Body

Abstract

The dynamic motion of an axisymmetric bluff body that is free to precess in pitch, yaw, and roll as a response to flow-induced aerodynamic loads is investigated in open-and closed-loop flow control wind tunnel experiments at Re D < 2·10 5 . The body is coupled to an upstream wire-mounted sting through a low-friction hinge bearing within its front end that enables nearlyfree rotations in pitch (15), yaw (18), and roll (180). The attitude and displacement of the sting are dynamically manipulated in 6-DOF using eight support wires that are each connected to a servo actuator through an in-line load cell for monitoring the instantaneous tension. The aerodynamic loads on the body, and thereby its motion, are controlled through fluidic modification of its aerodynamic coupling to its near wake using four independently-controlled aft mounted synthetic jet actuators that effect azimuthally-segmented flow attachment over the model's tail end. The effects of actuation-induced, transitory changes in the model's aerodynamic loads are measured by its motion response using image tracking (600 fps) and the coupled evolution of the near-wake flow captured by high-speed (500 fps) stereo PIV. Flow control authority is demonstrated by feedbackcontrolled manipulation of the model's dynamic response when the sting is held stationary or when it is subjected to commanded transitory pitch-yaw trajectory disturbances. It is shown that this flow control approach can modify the stability and damping of the model's motion when the sting is stationary (e.g., suppression or amplification of its natural oscillations), and impose a desired directional attitude that is decoupled from the moving sting using actuation-effected disturbance rejection.

Upstream actuation for bluff-body wake control driven by a genetically inspired optimization

“…In addition, in Dalla Longa et al (2017) the momentum coefficient was set to low values only after a high momentum coefficient stabilized the wake. Considering higher-Re applications, the momentum coefficient reaches values up to two order of magnitude larger than the one used in the present study (Barros et al 2016;Lambert, Vukasinovic & Glezer 2016;Li et al 2017;Lambert, Vukasinovic & Glezer 2018;Li et al 2019). In the literature, there also appear a series of bluff-body flow control studies at a much lower Re = 800-1200 (Qu et al 2017;Ma & Feng 2019).…”

Unsteady Roll Moment Control Using Active Flow Control on a Delta Wing

“…Control effectors based on active flow control (AFC) techniques offer the potential for increased control authority when the flow is separated. Examples of AFC for vehicle flight control include axisymmetric bluff body trajectory control using synthetic jet actuators, which is being investigated by Lambert et al [11]. Unsteady lift and pitching moment control on nominally 2-D wings has been explored by Woo et al [17,18], An et al [1], and Reißner [13].…”