FLOW VISUALIZATION STUDIES AROUND A STATIONARY AND OSCILLATING SQUARE CYLINDER WITH AND WITHOUT INTERFERENCE

摘要

Flow visualization studies have been carried out on a square cylinder under isolated and interference conditions (where another square cylinder is placed besides the test square cylinder). These are conducted to understand the flow fields around a square cylinder in such situations enabling to assess how much it is prone to flow-induced oscillations. Similar flow visualization studies have been conducted for circular cylinder also, in an attempt to bring out the influence of geometry. For some of the flow situations considered, correlation has been made with the aerodynamic response of the square cylinder (obtained through wind tunnel studies). Between the interfering cylinder (side dimension b), and the test cylinder (upstream cylinder; side dimension B), size ratios of b/B = 0.5, 1.0, 1.5, and 2.0 have been used. Various configurations such as tandem, side-by-side, and staggered arrangements have been tested with the two cylinders. Among many cases considered, only a few typical cases have been presented here. Results indicate that the flow field around a square cylinder is very much influenced due to interference effects and is found to depend on the spacing as well as on the size ratio between the cylinders. Comparison with the results on a circular cylinder reveals the influence of geometry. The observed flow field features are compared with those of earlier related studies, in some of the cases.