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Vlad – Flaviu ZEGREAN



Marilena GLOVNEA



Department of Applied Mechanics, University “Stefan cel Mare” of Suceava, ROMANIA


Abstract. Although the thickness of EHD oil films should vanish at very low rolling speeds, experimental investigations indicate that often this thickness does not fall below a remnant value of 10-30 nm. Initially, this phenomenon was attributed to a much higher viscosity near the wall than in the bulk, according to an empirical formula. Recently, theoretical physical background of the phenomenon was advanced by means of molecule-wall interaction potential. It was shown that, besides viscosity, shear modulus and limiting shear stress are enhanced in the neighborhood of the wall. These theoretical findings predict correctly experimentally found thin film thickness. New experimental evidence is needed to support theoretical results. This paper provides experimental results concerning the evaluation of structural flow units, minimum intermolecular potential and limiting shear stress in thin layers.


Keywords: liquid-wall interaction, viscosity, shear modulus, limiting shear stress, molecular layer




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