Pulse modulation of synthetic jet actuators for control of separation

Thomas T. Rice, Keith Taylor, and Michael Amitay
Phys. Rev. Fluids 6, 093902 – Published 24 September 2021

Abstract

It is postulated that the pulse modulation of synthetic jet actuators at or close to the natural shedding frequency of a separated flow over an airfoil can control the shedding of vorticity, and thus the load variation exerted onto an airfoil during dynamic stall more effectively than continuous sinusoidal actuation. The forces and flowfields on and around the airfoil were used to determine the mechanism by which pulse-modulated synthetic jet actuators interact with the separated shear layer in both static and dynamic pitch conditions. Both Eulerian and Lagrangian (finite-time Lyapunov exponent) vortex identification techniques were used to identify these interactions. It was shown that pulse modulation can improve many aspects of dynamic stall control with only 35% of the power consumption compared to continuous actuation. Both shallow and deep dynamic stall cases were explored, where the hysteresis in the lift coefficient was reduced when compared to the continuously actuated case. The flowfields during deep dynamic stall showed a dramatic reduction in the size of the wake as compared to the continuously-actuated case when flow separation was present. The Largangian coherent structure analysis described the interaction of the synthetic jet actuators with the separated shear layer at static angles of attack. Analysis of the change in circulation through the wake of the airfoil suggested pulse modulation reduces load excursions by reducing the maximum circulation shed from the suction side during stall inception, and increasing the circulation shed during flow reattachment, leveling out circulation shedding while not mitigating the total circulation, or vorticity, shed. The benefits obtained by utilizing pulse modulation suggest that actuating the synthetic jets with a pulse modulation signal may have a valuable place in the use of these actuators to control dynamic stall, and a mechanism by which this is achieved is proposed.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
14 More
  • Received 11 March 2021
  • Accepted 13 August 2021

DOI:https://doi.org/10.1103/PhysRevFluids.6.093902

©2021 American Physical Society

Physics Subject Headings (PhySH)

Fluid Dynamics

Authors & Affiliations

Thomas T. Rice, Keith Taylor, and Michael Amitay*

  • Department of Mechanical, Aerospace, and Nuclear Engineering Rensselaer Polytechnic Institute, Troy, New York 12180, USA

  • *Corresponding author: amitam@rpi.edu

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 6, Iss. 9 — September 2021

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Fluids

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×