Lift forces on a circular cylinder in cross flow resulting from heat/mass transfer

• Autores: Z. Trávnícek, F. Marsík, T. Vít, Z. Broucková, M. Pavelka
• Localización: Computational methods and experimental measurements / G. M. Carlomagno (ed. lit.), Carlos A. Brebbia (ed. lit.), Santiago Hernández (ed. lit.), 2013, ISBN 978-1-84564-732-2, págs. 149-159
• Idioma: inglés
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• Resumen

  • The well-known Magnus effect is the phenomenon responsible for the curved streamlines around rotating cylinders or balls. In other words, the phenomenon causes the curved motion of spinning balls and missiles. A related application is the Flettner rotor ship, which was designed to use the Magnus effect for propulsion. More generally, the Kutta-Joukowski theorem determines lift as the product of upstream velocity, fluid density, and circulation. Flow visualization experiments of cylinders in a cross flow demonstrate this effect. For comparison purposes, a classical potential solution is presented with the same parameters (with the Reynolds number of 920). The present study assumes that similar effects can be created by means of a non-symmetrical heat/mass transfer from a section of the bluff body. A theoretical model was derived, based on equations of momentum, mass, and energy balance. The derivation utilized the terms of the entropy gradient, and the resulting velocity circulation around the body. A circular cylinder with a mass transfer surface was suggested. The mass transfer, namely the evaporation of water, is proposed through a selected 90º segment of the cylinder surface.