Numerical study of vortex-induced vibration of an array of elliptic cylinders*

Harbor seals are able to track and hunt fish in low-visibility conditions by detecting fish swimming vortices through whiskers around their muzzle. To study such an operating principle of seal whiskers, we design an elliptic cylinder array in a circular arrangement to simulate this behavior. The cross-section of the whisker is equivalent to a two-dimensional ellipse with an aspect ratio of 2 and mass ratio of 2, and immersed in the laminar regime. Since the whisker will deflect under the influence of hydrodynamic force and affect the flow field accordingly, fluid-structure coupling calculation should be introduced to obtain the real vibration, that is, two-degree-of-freedom vortex-induced vibration (VIV) simulation of the entire array. The present work studies the remote coupling of flow around an elliptic cylinder array by analyzing the transverse and longitudinal response amplitudes, aerodynamic coefficients, Strouhal number, phase portrait, time response, orbital trajectory and wake mode pattern, and compares it with a single elliptic cylinder to reveal the characteristics of VIV of elliptic cylinder array, which lays a foundation for further study of flow characteristics of real whisker arrays.