Applied Scientific Research

, Volume 33, Issue 5–6, pp 427–435 | Cite as

Turbulent boundary layer velocity profiles over a smooth surface

  • P. A. Aswatha Narayana
Article
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Abstract

Mean velocity measurements made for two-dimensional incompressible turbulent boundary layers, for 3 pressure gradients on a smooth wall have been used to evaluate the pressure gradient parameter, the skin-friction and the roughness function by the method of “curve-fit” to the entire profile. Local skin-friction coefficients so obtained do not agree with the experimental results but the integral parameters are well represented.

Keywords

Turbulent Boundary Layer Adverse Pressure Gradient Smooth Wall Momentum Thickness Roughness Effect 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Nomenclature

C

surface roughness function value for just turbulent flow, equation (2)

cf

local skin-friction coefficient

fc

pressure gradient function (= (1−cos αη)/(1−cos α)), equation (2)

H

shape parameter (= δ*/θ)

K

profile factor (= 2.5(cos α−1)/α sin α=2.5 for flat plate)

Rx

Reynolds number (= Ux/ν)

Rχ

Reynolds number (= Uδ/ν)

Rδ

Reynolds number (= Uθ/ν)

U

free-stream velocity

U+

R θ

u

mean velocity in the boundary layer in streamwise direction at a distance y from the surface

u+

U/u τ

uτ

friction velocity

x

distance from the effective origin along the plate of the turbulent boundary layer

y

vertical distance perpendicular to wall

α

parameter depending on K, equation (2)

β

roughness function

δ

boundary layer thickness

δ*

boundary layer displacement thickness

θ

boundary layer momentum thickness

η

y/δ

ν

kinematic viscosity of the fluid

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References

  1. [1]
    Allan, W. K., J. Mech. Engng. Sci. 12 (1970) 391.Google Scholar
  2. [2]
    Allan, W. K. and V. Sharma, J. Mech. Engng. Sci. 16 (1974) 71.Google Scholar
  3. [3]
    Aswatha Narayana, P. A., Turbulent flows over smooth and rough surfaces, Report No. LR 235, Dept. of Aerospace Engg. T.H. Delft, 1977.Google Scholar
  4. [4]
    Coles, D. and E. A. Hirst, Computation of turbulent boundary layers, AFOSR-IFP Stanford Conference, 1969.Google Scholar

Copyright information

© Martinus Nijhoff 1977

Authors and Affiliations

  • P. A. Aswatha Narayana
    • 1
  1. 1.Dept. of Appl. Mech.Indian Inst. of Techn.MadrasIndia

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