The response of a parametrically excited hanging string in fluid

✍ Scribed by C.S. Hsu

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 581 KB
• Volume: 39
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1016/s0022-460x(75)80084-8

✦ Synopsis

The straight and vertical configuration of a hanging string in fluid may become unstable if the support point undergoes an up-and-down motion with its frequency and amplitude satisfying certain conditions. When this occurs a certain mode is parametrically excited. In this paper a study is presented of the role playe d by the ~;'elocity square damping of the fluid in limiting the amplitude growth of such an unstable mode. A simple formula is derived which allows one to compute, to the first order of approximation, the steadystate response amplitude. It is found that the amplitude, in its dimensionless form, may be expressed in terms of a frequency parameter, D, an excitation strength parameter, F, a drag coefficient, Co, a displaced mass ratio parameter, r.u, and the mode number.