Abstract
Results of a study of the optical response of liquid crystals with helical supramolecular structure to surfacefriction-induced shear stress in aerodynamic experiments are reported. The effect of re-orientation of molecules from confocal (light-scattering) to planar (selectively reflecting light) texture is considered. The textural transition is examined by the spectral and colorimetric methods. Dependences of the reflection spectra of the formed planar texture on time and on the mean shear-stress level were obtained. It is shown that the dependence of the texture transition time on the shear-stress level can be approximated, in a logarithmic scale, with a linear dependence; this allows using the effect for flow diagnostics.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
J.V. Naughton and M. Sheplak, Modern developments in shear-stress measurement, Progress in Aerospace Sciences, 2002, Vol. 38, P. 515–570.
V.A. Belyakov and A.S. Sonin, Optics of Cholesteric Liquid Crystals, Nauka, Moscow, 1982.
V.I. Kornilov, Reduction of turbulent friction by active and passive methods (Review), Thermophysics and Aeromechanics, 2005, Vol. 12,No. 2, P. 175–196.
P. Bonnett, T.V. Jones, and D.G. McDonnell, Shear-stress measurement in aerodynamic testing using cholesteric liquid crystals, Liquid Crystals, 1989, Vol. 6,No. 3, P. 271–280.
D.J. Mee, T.W. Walton, S.B. Harrison, and T.V. Jones, A comparison of liquid crystal techniques for transition detection: AIAA Paper, 1991, No. 91-0062, 8 p. (29th Aerospace Sciences Meeting, Jan. 7–10, 1991).
G.M. Zharkova, V.N. Kovrizhina, V.A. Mukhin, S.P. Podyachev, and V.M. Khachaturyan, Application of liquid crystals for study of heat transfer and flow structure in a channel with corrugated walls, Thermophysics and Aeromechanics, 2002, Vol. 9, No. 1, P. 99–106.
G.M. Zharkova, V.N. Kovrizhina, and V.M. Khachaturyan, Visualization of flow structure in a channel with corrugated walls by liquid crystals, J. Visualization, 2002, Vol. 5,No 4, P. 311.
US Patent 5 438 879, Reda D.C., 1995.
D.S. Parmar, A novel technique for response function determination of shear-sensitive cholesteric liquid crystals for boundary layer investigations, Review of Sci. Instruments, 1991, Vol. 62,No. 6, P. 1596–1608.
D.C. Reda and J.J. Muratore, Measurement of surface shear stress vectors using liquid crystal coatings, AIAA J., 1994, Vol. 32, P. 1576–1582.
G.M. Zharkova, V.N. Kovrizhina, and A.P. Petrov, Experimental study of thin-film liquid crystal coatings for panoramic diagnostics of shear stress distribution on the model surface, in: Proc. XV Int. Conf. on the Methods of Aerophysical Research, 1–6 November, Novosibirsk, Russia, 2010, Pt 1, P. 253–254.
G.M. Zharkova, V.N. Kovrizhina, A.P. Petrov, E.S. Shapoval, V.E. Mosharov, and V.N. Radchenko, Visualization of boundary layer transition by shear sensitive liquid crystals, in: Proc. 8th Pacific Symp. on Flow Visualization and Image Processing, 21–25 August, Moscow, Russia, 2011, No. 113, P. 1–5
A.M. Kharitonov, Techniques and Methods of Aerodynamic Experiment, Pt. 2, Methods and Means for Aerophysical Measurements: Student’s Guide, Novosibirsk, Novosibirsk State Tech. University, 2007.
V. Patel, Calibration of Preston tube and limitations on its use in pressure gradient, J. Fluid Mech., 1965, Vol. 23,Pt. 1, P. 185–208.
M.M. Gurevich, Color and Color Measurements, Moscow, Leningrad, USSR Acad. Sci., 1950.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Zharkova, G.M., Kovrizhina, V.N. & Petrov, A.P. Experimental study of a textural transition in liquid crystals under shear stress induced by surface friction. Thermophys. Aeromech. 20, 309–316 (2013). https://doi.org/10.1134/S0869864313030062
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0869864313030062