Author(s)

S. Malavasi, E. Zappa & A. Cigada

Abstract

The main goal of this paper is to investigate the effects of an asymmetric confined flow developing around a cylinder with a rectangular cross-section at different attack angles. Previous studies faced this problem analyzing change of the drag and lift force coefficients due to the proximity of a fixed plate parallel to the mean flow and fixed in the vicinity of the cylinder. In this paper an original application of particle image velocimetry technique was used to investigate the mean fluid structures around rectangular cylinders with aspect ratios of 3 and 4. The kinematics characterization of the flow field has been quantified through the transversal dimension of the wake and the position of the stagnation point on the frontal area of the obstacle. These parameters have been compared with the mean force coefficients on the cylinder. The non-symmetric boundary conditions were obtained in an open chamber wind tunnel, putting a fixed plate parallel to the mean flow at one side of the cylinder; on the other side an almost free flow can be assumed. The comparison between the kinematics parameters of the flow structure and the dynamic coefficients provides useful information to the phenomenon understanding. Keywords: confined flow, rectangular cylinder, flow induced loading. 1 Introduction The paper focuses on providing new insights and knowledge of the mechanisms governing the flow field around a tilted rectangular cylinder near a solid wall, with particular attention to the study of the mean flow around the cylinder. The problem of fluid dynamic forces acting on a rectangular cylinder was studied by different Authors, such as Naudasher and Wang [3], Norberg [4] and Deniz and Staubli [5] that considered the cylinder immersed in unbounded flow.

Keywords

confined flow, rectangular cylinder, flow induced loading.