Hydroelastic Analysis of Ships using a High-Order Finite Difference Method on Overlapping Grids

In this paperwe present some recent results for predicting the hydroelastic response of large ships from linear potential flow theory combined with either Euler-Bernoulli or Timoshenko beam models of the hull girder. We have extended our in-house seakeeping solver, OceanWave3D-seakeeping, to include generalized modes in order to capture the wave-induced vertical bending motions of the hull at both zero- and non-zero forward speed. Both Neumann-Kelvin and double-body flow linearizations are applied and compared using three ship-like test cases. Two forms of the hydrostatic restoring force coefficients for flexible modes exist in the literature (Newman’s form and Malencica et al.’s form). We compare results from these two models and find that they give nearly the same motion response for a typical ship. For a relatively flexible ship, significant differences are found in the bending response predicted by the Euler-Bernoulli and Timoshenko
beam models. Forward speed is found to increase the likelihood of resonant response in the bending modes.