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Wind Actions - Vortex Shedding

  1. Oct 31, 2011 #1
    Please Help!

    In dealing with wind induced forces, caused by vortex shedding action over a circular cylinder, we must calculate the parameter "Kw" (effective correlation factor), which depends on "L/b", "L" beeing the "correlation lenght" (Eurocode).

    Is there any method, analytical (or empirical), we could use, in order to calculate the parameter "L"?

    I do thank you for any kind of help!

    Best regards

    Luís Fernando
  2. jcsd
  3. Oct 31, 2011 #2
    Could you define your variables?
  4. Nov 1, 2011 #3
    Thank you, "RandomGuy88"!

    According to Eurocode, the largest displacement "Ymáx/b", due to vortex shedding, can be calculated using expression:

    Ymáx/b = 1/St^2 x 1/Sc x K x Kw x Clat

    I can determinate all of them, except "Kw", which is a function of the so called "correlation lenght" ("L"), which, in turn, is a function of "Ymáx".

    And that´s the problem! How can I calculate "L"?

    Sorry, if I was too much problematic, and for my bad english!

    Best Regards

    Luís Fernando
  5. Nov 2, 2011 #4
    I have no idea what any of your variables mean. What is b, what is Ymax, what is St, Sc, K....

    Is L length over which turbulent velocity fluctuations are correlated? Or is something completely different?
  6. Nov 3, 2011 #5
    Hi, RandomGuy88!

    The meaning of those variables, is:

    b - Crosswind dimension
    Ymax - Maximum displacement due to vortex shedding
    St - Strouhal number
    Sc - Scruton number
    K - Mode shape factor
    L - Lenght over which vortex shedding occurs
    Kw - Effective correlation lenght factor

    (See Eurocode 1 - Action on Structures - Part 1-4 - General Actions - Wind Actions)

    Best Regards

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