Experimental study on fluidic control of a diffuser: influence of slit geometry

Erik Smid, Hans van Noort, Avraham Hirschberg, Ellen van Emden, Hein de Vries, Herman Stobbe, Guido Zwart, Harry Hoeijmakers

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    1 Citation (Scopus)


    Experiments on fluidic control in an asymmetric diffuser are described. For fluidic control, fluid injection through a cross-flow slit placed upstream of the diffuser is applied. Both continuous and oscillating fluid injection is considered. Geometries of slit edges, slit width and partitioning of the slit have been varied. The control strategies combine three elementary processes: momentum injection in the flow direction, removal of the boundary layer by suction and enhancement of turbulent mixing by means of large scale 3-D vortical-flow structures. Momentum injection is only beneficial when the injection velocity is higher than the main flow velocity. In particular velocities of half the main flow velocity turn out to be most detrimental. Suction remains quite efficient even at low velocities. This explains why oscillating flow with low amplitudes is more efficient than flow with moderately high amplitudes. Partitioning of the slit does clearly promote fluidic control by inducing 3-D vortical-flow structures.
    Original languageEnglish
    Title of host publication47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
    Subtitle of host publication5-8 January 2009, Orlando, Florida
    EditorsRob Vermeland
    Place of PublicationReston, VA, USA
    PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
    ISBN (Print)1-56347-969-9
    Publication statusPublished - 5 Jan 2009
    Event47th AIAA Aerospace Sciences Meeting 2009: including The New Horizons Forum and Aerospace Exposition - Orlando, United States
    Duration: 5 Jan 20098 Jan 2009
    Conference number: 47


    Conference47th AIAA Aerospace Sciences Meeting 2009
    Country/TerritoryUnited States


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