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Lubricants 2018, 6(1), 25; https://doi.org/10.3390/lubricants6010025

# Reducing Friction with a Liquid Film on the Body Surface

1
Department of Mechanics, Samara State Technical University, Molodogvardeyskaya Street, Building 244, Samara 443100, Russia
2
Department of Aerogasdynamics and Heat Transfer, Joint Stock Company Space Rocket Centre Progress, Zemetsa str., Building 18, Samara 443009, Russia
*
Author to whom correspondence should be addressed.
Received: 23 January 2018 / Revised: 22 February 2018 / Accepted: 27 February 2018 / Published: 7 March 2018
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# Abstract

A flow of a thin layer of liquid is simulated on a flat surface of a body located in a stream of air. Liquid film on the surface of the body reduces frictional resistance and can be used as a boundary layer control element. The paper presents a mathematical model of the film flow on a half-plane, located at an angle to the horizon. The fluid flow is determined by the force of gravity and friction from the external air current. A model of an incompressible viscous fluid is used in the boundary-layer approximation. The terms of the motion equation are averaged over the film thickness according to the Leibniz rule. In the cross section of the film, a quadratic law is adopted for the distribution of the longitudinal velocity, taking into account friction on the film surface. An analytical solution of the problem is obtained in the form of series in powers of the small parameter for determining the film thickness and the average longitudinal velocity along the length of the plate. It is shown that the friction decreases with flow around a half-plane with a film of liquid on the surface. View Full-Text
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

MDPI and ACS Style

Klyuev, N.; Polyakov, K.; Krutovertseva, A. Reducing Friction with a Liquid Film on the Body Surface. Lubricants 2018, 6, 25.

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

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