On Parameters Defining Active Flow Control

Emile K. Oshima, Morteza Gharib, Johannes Reichert, Israel J. Wygnanski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

There is a conceptual difference between Boundary Layer Control (BLC) and Active Flow Control (AFC). The former aims to compensate for frictional losses in the boundary layer, while the latter seeks to exploit instabilities in the flow to alter its character. The momentum coefficient _` has been the parameter of choice to characterize boundary layer energization and circulation enhancement by blowing. While it has proven useful in cataloging some data, it is not a universally valid single parameter describing the complex flow over wings. Furthermore, the jet velocity and density required for its calculation are difficult to measure in situ, necessitating unrealistic assumptions or extensive calibrations. The best quantity to be used is one that defines the energy requirements of an entire system while realizing its lack of uniqueness. Experimental investigations on a thick flapped airfoil and a simple swept wing of different sweep angles and aspect ratios demonstrate that such a quantity is more suitable for design purposes because it shifts the perspective from detailed jet flow to system needs. Although this figure-of-merit approach black boxes flow interaction details between the jet and the freestream, system-based coefficients can still provide various physical insights in their capacity as cataloguing parameters.

Original languageEnglish (US)
Title of host publicationAIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624106101
DOIs
StatePublished - 2021
Externally publishedYes
EventAIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021 - Virtual, Online
Duration: Aug 2 2021Aug 6 2021

Publication series

NameAIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021

Conference

ConferenceAIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021
CityVirtual, Online
Period8/2/218/6/21

ASJC Scopus subject areas

  • Aerospace Engineering
  • Energy Engineering and Power Technology
  • Nuclear Energy and Engineering

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