Actuator selection and placement for localized feedback flow control

Research output: Contribution to journalArticlepeer-review


The selection and placement of actuators and sensors to control compressible viscous flows is addressed by developing a novel methodology based upon the eigensystem structural sensitivity of the linearized evolution operator appropriate for linear feedback control. Forward and adjoint global modes are used to construct a space of possible perturbations to the linearized operator, which yields a small optimization problem for selecting the parameters that best achieve the control objective, including where they should be placed. The method is demonstrated by informing actuation to suppress amplification of the instabilities in boundary layer separation in a high-subsonic diffuser. Complete stabilization is observed in the separated shear layer for short downstream distances at modest Reynolds number. Higher Reynolds numbers and longer distances are expected to be more challenging to stabilize; here the control informed by the procedure still substantively suppresses amplification of instabilities. It is also demonstrated that more complex actuator-sensor selections may not yield superior controllers.

Original languageEnglish (US)
Pages (from-to)775-792
Number of pages18
JournalJournal of Fluid Mechanics
StatePublished - Dec 25 2016


  • Absolute/convective instability
  • boundary layer control
  • control theory

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics


Dive into the research topics of 'Actuator selection and placement for localized feedback flow control'. Together they form a unique fingerprint.

Cite this