Hydro-elasticity of Two Side-by-side Flexible Cylinders

In this paper, we present the effects of proximity interference on the hydro-elastic responses of two pre-tensioned flexible cylinders in side-by- side arrangement subjected to uniform cross-flow (CF). The experimental results of the side- by-side cylinders are presented and compared with an isolated flexible cylinder. Two flexible cylindersof the same size, properties, and pretensions were tested with two different vertical separation distances, namely,2.75 and 5.5 diameters. Reynolds numbers ranged from 1400 to 20000 (subcritical regime). The aspect ratio of the cylinders was 162 (length over diameter). The mass ratio (cylinder’s mass over mass of displaced water) was 1.17. It was found that at the small separation distance of 2.75 diameters, the upper cylinder showed no upperbranch in the first CF lock-in region, in contrast to the lower and the single cylinder. With the increase in the initial vertical separation to 5.5 diameters, both cylinders exhibit amplitude responses similar to the isolated cylinder. At the small separation distance, the upper cylinder showed quite a distinct CF frequency response (higher values) than both the lower cylinder and the single cylinder within the reduced velocity range of 4 < Ur < 6.74.

کلیدواژه ها:

Side-by-side ، Flexible cylinders ، Amplitude response ، Frequency response