Fluid Flow and Heat Transfer around a Rectangular Cylinder (The Case of a Width/Height Ratio of a Section of 5 - 9)

摘要

It is well known that the aerodynamic characteristics of a rectangular cylinder changes drastically at about c/d = 0.67, 2.8 and 6.0, when the width/height ration c/d of the cylinder increases systematically [1-4]. At c/d = 0.67, the position of vortex formation comes close to the rear face of the cylinder, then the drag coefficient has the maximum value. Beyond c/d > 2.8, the shear layer separated from the cylinder reattaches periodically to the side face of the cylinder and the Strouhal number increase drastically. Moreover, the Strouhal number increases discontinuously at about c/d = 6.0. One of the authors investigated the local and averaged heat transfer around rectangular cylinders of c/d = 0.2 to 5.0. [6-11]. Recently, Sparrow et al. [12] recommend that modern correlations for average heat transfer coefficient for square and rectangular cylinders which reported by Igarashi [6-11] are adopted in the heat transfer textbook in future. Reports of rectangular cylinder with c/d > 6.0 have apparently not been published. In this paper, it is shown that the local heat transfer coefficient around the cylinders with c/d = 5 to 9 are closely correlated to flow characteristics.