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A novel technique for response function determination of shear sensitive cholesteric liquid crystals for boundary layer investigationsA description of the design and setup of an experimental technique for measurement of the response function in shear sensitive liquid crystals has been reported. Utilizing the selective reflection characteristics of cholesteric liquid crystals, the method is capable of measuring the delay, rise, and relaxation times in response to a given dynamic shear stress as a function of the wavelength of the incident light. Application of a step input shear stress results in a liquid crystal time response that can be described as consisting of an initial delay, a shear induced helix deformation, and a relaxation to the initial state through diffusion processes. The method has been used for quantitative calibration of a shear sensitive liquid crystal by observing the peak in reflected light intensity, at a given wavelength, as a function of the shear stress.
Document ID
19910055731
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Parmar, D. S.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 15, 2013
Publication Date
June 1, 1991
Publication Information
Publication: Review of Scientific Instruments
Volume: 62
ISSN: 0034-6748
Subject Category
Instrumentation And Photography
Accession Number
91A40354
Distribution Limits
Public
Copyright
Other

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