Dynamic Response of Elastic Cylinders in Fluid Layer

The dynamics of multiple cylindrical elastic beams in a horizontal fluid layer are examined. The hydrodynamic interaction forces on the cylinders, due to the base motion of the entire array, are formulated, and these forces are applied to an elastodynamic beam equation to investigate both the beam-fluid and the beam-fluid-beam interaction. The fluid is taken to be water and is assumed to be linearly compressible and represented by potential flow theory. The cylindrical beams are modeled by Euler-Bernoulli beam theory. The hydrodynamic force distribution, mode shapes, and the frequency response of the beams to harmonic base excitation are presented. The multiple cylinder fluid interaction has significant effects in the dynamic response of the system, particularly for frequencies higher than the first natural frequency of a free beam. The interaction response is strongly dependent on the direction of the base excitation.