Accession Number:

ADA214958

Title:

Velocity Profile and Wall Shear Stress Measurements for a Large Eddy Break-Up Device (LEBU)

Descriptive Note:

Technical rept.

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE ACOUSTICS AND VIBRATION LAB

Personal Author(s):

Report Date:

1989-11-02

Pagination or Media Count:

60.0

Abstract:

Wind tunnel experiments were performed in the M.I.T. Acoustics Vibrations Laboratory to determine the reduction in mean wall shear stress achieved by honeycomb matrix Large Eddy Break-Up Device LEBU and study how such a device alters a turbulent boundary layer. The LEBUs considered significantly altered the steady and unsteady velocity components, and moved the active region of the boundary layer further from the wall. The LEBUs studied achieved at least a 10 reduction of mean wall shear stress for distances over 300 displacement thicknesses behind the device. The LEBU parameter of height was found to affect the level and duration of mean wall shear stress reduction. Surface fence measurements indicated that the boundary layer manipulated by the LEBU does not adhere to the Coles Law of the Wall , possessing a large B intercept. Keywords Boundary layer manipulation Wall shear stress reduction Fluid dynamics Eddy currents. kt

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE