The transient response of an ice shelf to an incident wave packet from the open ocean is studied with a model that allows for extensional waves in the ice shelf, in addition to the standard flexural waves. Results are given for strains imposed on the ice shelf by the incident packet, over a range of peak periods in the swell regime and a range of packet widths. In spite of large differences in speeds of the extensional and flexural waves, it is shown that there is generally an interval of time during which they interact, and the coherent phases of the interactions generate the greatest ice shelf strain magnitudes. The findings indicate that incorporating extensional waves into models is potentially important for predicting the response of Antarctic ice shelves to swell, in support of previous findings based on frequency-domain analysis.

Hydroelectric turbine designers need to know the damping coefficient of a turbine blade to assess its longevity. Damping is difficult to simulate numerically. Current flow-added damping evaluation methods involve solving Reynolds-averaged Navier–Stokes simulations, which are numerically expensive and complex. This paper presents a new, simple and fast method to evaluate the added damping coefficient of a standalone and straight hydrofoil using NASTRAN's multiple modules. Using the vacuum and resting fluid natural frequencies, a proportionality matrix is implemented into NASTRAN's flutter solution using the added virtual mass incremental factor to evaluate the added damping adequately. The methodology is validated against experimental and numerical data from previously published articles and presents good agreement with existing results.

A coupled finite/boundary element method to approximate the free vibration modes of an elastic structure containing an incompressible fluid is analyzed in this paper. The effect of the fluid is taken into account by means of one of the most usual procedures in engineering practice: an added mass formulation, which is posed in terms of boundary integral equations. Piecewise linear continuous elements are used to discretize the solid displacements and the fluid-solid interface variables. Spectral convergence is proved and error estimates are settled for the approximate eigenfunctions and their corresponding vibration frequencies. Implementation issues are also discussed and numerical experiments are reported.