NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Visualization and Measurement of Surface Shear Stress Vector Distributions Using Liquid Crystal CoatingsWhen a shear-sensitive liquid crystal coating is illuminated from the normal direction by white light and observed from an oblique above-plane view angle, its color-change response to shear depends on both shear stress vector magnitude and the direction of the applied shear vector relative to the observer's in-plane line of sight. At any point, the maximum color change is always seen or measured when the local shear vector is aligned with, and directed away from, the observer; the magnitude of the color change at this vector/observer aligned orientation scales directly with shear stress magnitude. Conversely, any point exposed to a shear vector with a component directed toward the observer exhibits a noncolor-change response, always characterized by a rusty red or brown color, independent of both shear magnitude and direction. Based on this knowledge, full-surface shear stress vector visualization and measurement methodologies were formulated and successfully demonstrated. The present paper reviews the observations and measurements that led to the development of these methodologies and applications of both are discussed.
Document ID
19980204011
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Reda, Daniel C.
(NASA Ames Research Center Moffett Field, CA United States)
Wilder, Michael C.
(MCAT Inst. San Jose, CA United States)
Date Acquired
August 18, 2013
Publication Date
May 1, 1998
Subject Category
Fluid Mechanics And Heat Transfer
Funding Number(s)
CONTRACT_GRANT: NAS2-14109
Distribution Limits
Public
Copyright
Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available