1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Separating a higher-order ODE into 1st-order ODEs

  1. Sep 17, 2006 #1
    Normally I can do these, and I'm fairly familiar with the equations used here, but for the life of me I can't figure this one out. Here's the question:

    The following equation is the known as Blasius boundary layer equation for the laminar flow over a flat
    plate in similarity variables:

    2f''' + ff'' = 0
    [itex]\eta[/itex] = 0, f' = f = 0
    [itex]\eta[/itex] --> inf, f' --> 1


    [tex]\eta = \frac{y}{x} \sqrt{\frac{U_{\infty}x}{\nu}[/tex]

    [tex]\frac{u}{U_\infty} = f'(\eta)[/tex]

    This'll look familiar to anyone else who knows fluid mechanics, I'm sure. The question requires me to solve this numerically using MATLAB, which I think I can figure out, but the methods we use require a series of 1st order ODES. I can't figure out how to separate this and it's driving me craaaaazy. Every method I try doesn't fit with the given boundary values. I've tried rearranging everything given there but I can't figure it out. Anyone got any ideas?
    Last edited: Sep 17, 2006
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted