Experimental investigation of the mutual interference flow of two circular cylinders by flow visualization

Abstract

Abstract. In order to understand the aspect of the mutual interference flow from two circular cylinders, the visual observation experiment was performed by use a water flow apparatus. The purpose of this study is accumulation of the basic image data for comparing with numerical computation or previous experimental results. In this report, the intervals of two circular cylinders were varied, the visualization experiment was performed, and the vortex shedding characteristics and the flow pattern in each case were investigated. The cylinder setting conditions were seven kinds (the position of the rear-side circular cylinder is changed). The cylinder diameter ratios were four kinds (D/d=1.0, 1.67, 2.5 and 5.0). The variation of Reynolds number was three kinds (Re=548.7, 1200 and 2500). The dye oozing streak method was used in this visualization experiment. Although the previous PIV experimental result and present result obtained the same flow feature, the aspect of an interference flow became clear by changing the color of tracer ink.

The study of water-head measurement shown in a single tube manometer by use of easy image-processing technique

“…Accordingly, it seems that it is not an error of measurement by the suggested measurement technique. When Reynolds number was Re=9800, it was obtained that it is well in agreement as compared with previous experimental data Re=1.1×10 5 . It supports the usefulness of this measurement technique that it was in agreement with the known profile by comparable Reynolds number.…”

The second frequencies in the wake behind two circular cylinders

“…It was dosed equally and in such a way that it did not break the boundary layer of the cylinder. A more detailed description, measurement parameters, and settings for this experimental device are given in [10]. For each recorded position and each Reynolds number, image data was obtained, which was then processed using the POD method.…”

“…In the case of two cylinders, 7 mutual positions were measured, which were chosen based on the research by Hwang and Choi present in [6] and Strykowski and Sreenivasan in [7]. The primary objective of these measurements was to investigate the effect of the second cylinder on the occurrence of disturbances and instabilities in the wake of the first cylinder, as mentioned in [8], [9] and [10]. Their coordinates are given in Table 1, pitch ratios (R) and angle of rotation (α).…”

The Aspect of the Flow Around a Circular Cylinder in a Free Surface Water Flow

“…In our research group, flow visualization observation of the around of a body has been carried out using water tank experimental apparatus (a closed circuit water channel and a towing water tank). And the aspect of various flows has been shown in comparatively low Reynolds number [1] [2]. These reports of research were carried out at stream velocity and towing velocity at which the water surface of the around of a body is not choppy in a water tank with a free surface.…”