Accession Number : ADA250700


Title :   Adaptive and Nonadaptive Feedback Control of Global Instabilities with Application to a Heated 2-D Jet


Descriptive Note : Final technical rept. 15 Jun 1989-31 Dec 1991


Corporate Author : CALIFORNIA UNIV LOS ANGELES SCHOOL OF ENGINEERING AND APPLIED SCIENCE


Personal Author(s) : Monkewitz, Peter A ; Mingori, D L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a250700.pdf


Report Date : Apr 1992


Pagination or Media Count : 63


Abstract : Close to the onset of self-excited fluid oscillations the generic complex Ginzburg-Landau is proposed as the lowest order model for the plant. Its linear part which provides the stability boundaries is derived from first principles for both doubly-infinite and semi-infinite flow domains. Concentrating on a single global mode, the model is further simplified to the Stuart-Landau equation. For this latter model a methodology is developed for the design of single-input single-output controllers. The so designed controllers have been implemented on a self-excited, heated two-dimensional jet with one hot wire as sensor and an acoustic speaker as actuator, and are shown to be effective within their limitations in suppressing or enhancing limit-cycle oscillations. Finally, the effect of of a controller designed to suppress the most unstable global mode on other modes is investigated experimentally in the wake of a cylinder at low Reynolds number, where an encouraging semi- quantitative correspondence to the Ginzburg-Landau model is found.


Descriptors :   *WAKE , *TWO DIMENSIONAL FLOW , *OSCILLATION , *BLUNT BODIES , *JET FLOW , *FLUID CONTROL , INPUT , OUTPUT , METHODOLOGY , GLOBAL , MODELS , ACOUSTICS , NUMBERS , HOT WIRE ANEMOMETERS , REYNOLDS NUMBER , ACTUATORS , FLUIDS , DIFFERENTIAL EQUATIONS , CYCLES , BOUNDARIES , LIMITATIONS , FEEDBACK


Subject Categories : Fluidics and Fluerics
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE