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Active techniques to control vortex shedding

  1. Dec 22, 2009 #1
    I am doing a paper regarding active techniques to control/manipulate vortex shedding in the near wake behind a 2D or axisymmetric bluff body, such as cylinder.

    May I know what are the available active techniques used in controlling vortex shedding?

    Thank you.
     
  2. jcsd
  3. Dec 22, 2009 #2
    I would look into active flow control devices, sparkjet or synthetic jet actuators. Report back with anything of interest that you find.
     
  4. Dec 22, 2009 #3

    minger

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    Here's a couple I found quickly:

    "Active Control of Cylinder Wake", Chen and Aubry, Communications in Nonlinear Science, 10(2005)

    The objective of this paper is to develop an efficient active control algorithm for manipulating wake flows
    past a solid cylinder in an electrically low-conducting fluid (e.g. seawater). The intent is to avoid both vortex
    shedding and flow separation from the body. It is expected to reduce the mean drag significantly. This is
    achieved through the introduction of a Lorentz force in the azimuthal direction generated by an array of
    permanent magnets and electrodes located on the solid structure. With the use of a symmetric and static
    Lorentz force over the entire surface of the cylinder, the vortex shedding behind the cylinder weakens and
    eventually disappears completely when the Lorentz force is sufficiently large.


    "FEEDBACK CONTROL OF VORTEX SHEDDING FROM A CIRCULAR CYLINDER BY ROTATIONAL OSCILLATIONS", Fujisawa, Kawaji, Ikemoto, Journal of Fluids and Structures (2001),15

    The present paper describes a new active method for controlling vortex shedding from
    a circular cylinder in a uniform #ow at medium Reynolds numbers. It uses rotary cylinder
    oscillations controlled by the feedback signal of a reference velocity in the cylinder wake. The
    e!ectiveness of this feedback control is evaluated by measuring the response of mean and
    #uctuating velocities in the cylinder wake, the spanwise correlation, the power spectrum, and
    the #uid forces acting on the cylinder. It is found that the velocity #uctuations and the
    #uid forces are both reduced by the feedback control with optimum values of the phase lag and
    feedback gain. The simultaneous #ow visualization synchronized with the cylinder oscillation
    indicates the attenuation as well as the mechanisms of vortex shedding under the feedback
    control, which is due to the dynamic e!ect of cylinder oscillation on the vortex formation
     
  5. Dec 22, 2009 #4
    I have done a search and found some papers on active techniques. But what I am looking for is if there are any few standard and common active techniques that people use to control vortex shedding.

    For example, when we mention flow speed measurement, the most common methods are using pitot-static tubes and hot wires etc.

    So are there any common active techniques to control vortex shedding?
     
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