2000 年 48 巻 562 号 p. 369-376
The fluid-structure interaction, especially the interaction between the elastic body and the ambient flow, is one of very complicated problems to be analyzed in engineering. The body is oscillated freely, consequently the information from the wake is fed back into the body motion. The interaction is a strong nonlinear one and it is so difficult to analyze it experimentally. In this article the problem on the oscillation of an elastic body is analyzed numerically, in which the features of the lock-in regime and the wake structure are made clear. The lock-in regime is captured clearly, in which the vortex shedding frequency, the body oscillation one, and the body eigen one are coincided each other and also the vortex street is redistributed to be switched over from one row to two. The self-limiting process is controlled by the phase difference between the body oscillation and the body forces (lift and force due to the virtual mass effect). Also the "pseudo-lock-in" regime is captured, in which, while the vortex shedding frequency and the body oscillation one are coincided each other, they are different from the body eigen one.