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Boundary Thickness Questions

  1. Jul 29, 2014 #1
    Calculate the thickness of the boundary Layer δ at a location x= 0.3m along the chord length of an aircraft wing at each of the following velocities. (u = 20, 40,60,80,100 knots)

    Assume ISA P=101325 R=287 T=288.5 μ =18 x 10-6

    (1)Re transition=5 x 10^5
    (2)δ Laminar = x 4.91 Rex^-0.5
    (3)δ turbulent = x 0.381 Re^-0.2

    Using Re= ρux/μ

    Re(20) =21008 Re (40)= 420175 Re (60)=630262 Re (80)= 840350 Re (100)= 1050233

    I'm not to sure where to go from here, do I have to substitute the Reynolds into the three equations if so which values do substitute.
  2. jcsd
  3. Jul 29, 2014 #2
    You know the reynold's numbers for each case, you know the characteristic length (x), you are given the Reynold's number for which the flow transitions from laminar to turbulent over a flat plate (the wing), and the equations for the boundary layer thickness for both states (laminar and turbulent).

    This one's a plug and chug, once you identify which streams are laminar and which are turbulent.
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