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Characteristics of steady horseshoe vortex system near junction of square cylinder and base plate / Chang Lin in Journal of engineering mechanics, Vol. 134 N°2 (Fevrier 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°2 (Fevrier 2008) . - pp. 184–197. Titre : Characteristics of steady horseshoe vortex system near junction of square cylinder and base plate Type de document : texte imprimé Auteurs : Chang Lin, Auteur ; Tsung Chun Ho, Auteur ; Subhasish Dey, Auteur Année de publication : 2008 Article en page(s) : pp. 184–197. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Vortices  Boundary  layers  Cylinders  Plates  Reynolds  number Résumé : This paper presents an experimental investigation on the characteristics of a horseshoe vortex system near the juncture of a square cylinder and a horizontal base plate, using particle image velocimetry and flow visualization technique. Experiments were conducted for Reynolds numbers (based on the free stream velocity and the width of square cylinder) ranging from 2.0×102 to 6.0×103 . The flow patterns are first classified into four major regimes: Steady horseshoe vortex system, periodic oscillation vortex system with small displacement, periodic breakaway vortex system, and irregular vortex system. The classifications can be demonstrated as a figure of Reynolds number versus the ratio of the height of square cylinder to undisturbed boundary layer thickness. The study then mainly focused on the characteristics of steady horseshoe vortex system (corresponding to Reynolds numbers ranging from 2.0×102 to 2.5×103 ). The nondimensional characteristics, including the horizontal and vertical distances from the primary vortex core to frontal face of the vertical square cylinder and bottom boundary of the base plate, respectively, the height of stagnation point at frontal face of the square cylinder, and the down-flow discharge as well as circulation of the primary vortex, all increase with increase of the ratio of the height of square cylinder to undisturbed boundary layer thickness. However, they all decrease with the increase of the aspect ratio (i.e., the height-to-width ratio) of the square cylinder. The study provides essential properties of a steady horseshoe vortex system and gives an insight for related engineering applications. It can be served as a basis for more complicated horseshoe vortex systems occurring at high Reynolds numbers. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A2%2818 [...] [article] Characteristics of steady horseshoe vortex system near junction of square cylinder and base plate [texte imprimé] / Chang Lin, Auteur ; Tsung Chun Ho, Auteur ; Subhasish Dey, Auteur . - 2008 . - pp. 184–197. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°2 (Fevrier 2008) . - pp. 184–197. Mots-clés : Vortices  Boundary  layers  Cylinders  Plates  Reynolds  number Résumé : This paper presents an experimental investigation on the characteristics of a horseshoe vortex system near the juncture of a square cylinder and a horizontal base plate, using particle image velocimetry and flow visualization technique. Experiments were conducted for Reynolds numbers (based on the free stream velocity and the width of square cylinder) ranging from 2.0×102 to 6.0×103 . The flow patterns are first classified into four major regimes: Steady horseshoe vortex system, periodic oscillation vortex system with small displacement, periodic breakaway vortex system, and irregular vortex system. The classifications can be demonstrated as a figure of Reynolds number versus the ratio of the height of square cylinder to undisturbed boundary layer thickness. The study then mainly focused on the characteristics of steady horseshoe vortex system (corresponding to Reynolds numbers ranging from 2.0×102 to 2.5×103 ). The nondimensional characteristics, including the horizontal and vertical distances from the primary vortex core to frontal face of the vertical square cylinder and bottom boundary of the base plate, respectively, the height of stagnation point at frontal face of the square cylinder, and the down-flow discharge as well as circulation of the primary vortex, all increase with increase of the ratio of the height of square cylinder to undisturbed boundary layer thickness. However, they all decrease with the increase of the aspect ratio (i.e., the height-to-width ratio) of the square cylinder. The study provides essential properties of a steady horseshoe vortex system and gives an insight for related engineering applications. It can be served as a basis for more complicated horseshoe vortex systems occurring at high Reynolds numbers. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A2%2818 [...]