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Journal of Flow Visualization and Image Processing
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN Druckformat: 1065-3090
ISSN Online: 1940-4336

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.v4.i2.10
pages 95-106

VISUALIZATION AND MEASUREMENT OF SKIN FRICTION USING THIN FILM INTERFEROMETRY

M. Ackman
Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803
T. J. Garrison
Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803

ABSTRAKT

An improved method for visualizing and measuring skin friction in complex, three-dimensional flows is described. The instrument, termed a Global Interferometer Skin Friction meter, is used to measure the local thickness of a thin oil film placed on a test model subject to aerodynamic shear. The oil film thickness is then related to the applied shear through lubrication theory. Through acquisition of a single image of the oil film interference pattern, the skin friction distribution can be obtained at any point covered by the film. Moreover, without any data analysis, the technique allows one to observe important qualitative information about the shear stress distribution over a test surface and the nature of the near wall flow. Images obtained during testing prove the GISF meter to be a useful tool for the visualization of the wall shear stress variation and separation lines in various complex flows. Results show the method provides numerous advantages over other shear measurement techniques. The instrument's configuration, theoretical background, and image-processing procedure are described. Additionally, the instrument's capabilities as a flow visualization tool are presented.