1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculating ylaminar, ybuffer and yturbulent using with Blasius Equation

  1. Aug 1, 2011 #1
    Calculating ylaminar, ybuffer and yturbulent using with Blasius Equation....

    1. The problem statement, all variables and given/known data

    How do you I calculate the Laminar Boundary Layer Y in meters with Blasius Equation?
    I have an expression for U (m/s) and u/U and u(m/s) and also eta=0.1, 0.2....5.2. I am wondering how one could calculate the y laminar boundary layer (m), the y buffer boundary layer (m), the ln y and the y turbulent boundary layer (m)... I know that I need different expression to calculate these...can someone tell me what expressions and how I get the y laminar/buffer/ln y/y turbulent?

    This is an example of the sheet I have:
    U (m/s) u/U u (m/s) Eta y lam (m) y buff (m) ln y y turb (m)
    252.7 0 0 0 ? ? ? ?
    252.7 0.047 11.8 0.1 ? ? ?
    252.7 0.0939 23.728 0.2 ? ? ? ?
    etc....

    2. Relevant equations

    I do think I can use the equation

    Eta= y*sqrt(U/nu*x)
    for ylaminar...but I have already found the tabulated data for Eta from Rosenhead's book in Laminar Boundary Layers...and I have the following X values:
    X=...
    25.91
    27.27
    28.94
    30.08
    32.64
    34.62
    36.19
    39.13
    41.99
    43.44
    44.57
    45
    44.57
    43.44
    41.99
    39.13
    36.19
    34.62
    32.64
    30.88
    28.94
    27.27
    25.91

    The following Eta values
    h
    0
    0.1
    0.2
    0.3
    0.4
    0.5
    0.6
    0.7
    0.8
    0.9
    1
    1.1
    1.2
    1.3
    1.4
    1.5
    1.6
    1.7
    1.8
    1.9
    2
    2.2
    2.4
    2.6
    2.8
    3
    3.2
    3.4
    3.6
    3.8
    4
    4.2
    4.4
    4.6
    4.8
    5
    5.2

    and U=252.7 m/s and u/U accordingly.

    3. The attempt at a solution
    For ylaminar do I only solve for y in the equation Eta= y*sqrt(U/nu*x)?
    If so, how what are the expressions for ybuffer, ln y (meaning which y should I take the log function on, the laminar, buffer or turbulent) and yturbulent? Can anyone pls help me? I am unsure about how to see when the transition starts so I can go from ylaminar to ybuffer/ turbulent based on my y values...I am grateful if anyone can help me. Thanks
     
  2. jcsd
  3. Aug 3, 2011 #2
    Re: Calculating ylaminar, ybuffer and yturbulent using with Blasius Equation....

    Why doesn't anybody even attempt to help me?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Calculating ylaminar, ybuffer and yturbulent using with Blasius Equation
Loading...