Infuence Of Free-Stream Turbulence On Boundary Layers

Authors

J. A. Hoffman, California Polytechnic State University
S. M. Kassir, California Polytechnic State University
Scott M. Larwood, California Polytechnic State UniversityFollow

Document Type

Report

Department

Mechanical Engineering

Report Number

ARC-12397

Funder

National Aeronautics and Space Administration (NASA)

Publication Date

6-1-1992

First Page

1

Last Page

55

Abstract

The influence of near isotropic free-stream turbulence on the shape factors and skin friction coefficients of turbulent boundary layers is presented for the cases of zero and mild adverse pressure gradients. With free- stream turbulence, improved fluid mixing occurs in boundary layers with adverse pressure gradients relative to the zero pressure gradient condition, with the same free-stream turbulence intensity and length scale. Stronger boundary layers with lower shape factors occur as a result of a lower ratio of the integral scale of turbulence to the boundary layer thickness, and to vortex stretching of the turbulent eddies in the free-stream, both of which act to improve the transmission of momentum from the free-stream to the boundary layers.

Recommended Citation

Hoffman, J. A.; Kassir, S. M.; and Larwood, Scott M., "Infuence Of Free-Stream Turbulence On Boundary Layers" (1992). All Faculty Reports - School of Engineering and Computer Science. 7.
https://scholarlycommons.pacific.edu/soecs-facreports/7