FLOW VISUALIZATION AROUND TWO SIDE-BY-SIDE RECTANGULAR CYLINDERS

摘要

Flow visualization in towing water tank has been made for flow around two side-by-side rectangular cylinders of different slender-ness b/h at various gap ratioes T/h, with Reynolds number around, 100-200. Buildings are often arranged in groups. The wind loadings acting on one of the buildings in group may be quite different from that of an isolated one due to the influence of the proximity or wake flow of other buildings. Unexpected flow phenomena may appear for the flows around a group of bodies. Many papers have been published recently on these subject, including in Japanese. One of the most interesting flow phenomena for two circular cylinders of side by side arrangement is the bistable biased gap flow which exists for certain gap ratioes. Thus, these two cylinders experience different drags and lifts. Biased flow also occurs for two plates and square cylinders with fixed separation points. The purpose of this paper is to study the visualization around rectangular cylinders, of different slenderness ratioes, arranged side by side at different gap ratioes. Special attentions are paid to the biased flow mentioned above. Visualization of the flow by means of eletrolytic-precipita-tion method is made in a water tank. The tank is 0.4m wide, 0.5m high and 6m long. Models are 10mm in windward side (defind as h) with the length in sideward (defind as b) changed with the slenderness. The experimental Reynolds number, defind as V~*h/y , is around 100-170. For b/h=0.0, we use two thin plates with their two end beveled.