Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can someone please explain to me the concept of vortex breakdown?

  1. Oct 14, 2008 #1
    Can someone please explain to me the concept of vortex breakdown?
     
  2. jcsd
  3. Oct 15, 2008 #2

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Re: Vortex

    Other than viscosity? Is there a particular instability you are thinking about?
     
  4. Oct 15, 2008 #3
    Re: Vortex

    Hi Andy,

    Thanks for your reply.Actually I dont understand the concept of vortex breakdown and its relation to Swirl Number (SN) which is defined as the ratio of swirl to meridianol motion strengths. I have read that vortex breakdown diappearance occurs as the SN decreases.
     
  5. Oct 15, 2008 #4

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Re: Vortex

    Yikes... I've never heard of a swirl number. My only resource is "Vortex Dynamics" by Saffman.

    I found a link here (http://www.enme.umd.edu/combustion/underwater_propulsion.htm) with some information that helped.

    If I understand your context, you are referring to a "vortex with helicity", which I think means that the vortex lines form axial screw patterns. The swirl number seems to be related to the pitch angle of the vortex lines, but I can't tell for sure. A vortex with helicity has moving vortex lines, which are then subject to instabilities.

    "Vortex breakdown" is a rapid change in the core radius of the vortex filament or tube- it was an experimentally-discovered phenomenon, and is characterized by a rapid increase in the core radius, which appears as a bubble or spiraling thread. Saffman claims there is no widely accepted theory for this phenomenon yet.

    In practical terms, it means that the relationship between the two is established empirically- by varying the swirl number (and other relevant parameters, for example capillary number, Reynolds number, Rossby number...)- this is glaringly missing from the above webpage. There's probably a lot of opportunity for original contributions to the topic.
     
  6. Oct 17, 2008 #5
    Re: Vortex

    Hi Andy,

    Thank you for your interest in my doubt. If you could assist me with your email address i could send you the document that i am trying to understand. Its on Vortex Breakdown. A pdf file.
     
  7. Oct 17, 2008 #6

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Re: Vortex

    Sashankhrao,

    I just sent you a personal message with my address. Hope I can help!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Can someone please explain to me the concept of vortex breakdown?
Loading...