The influence of level ice on the frequency domain response of floaters

The influence of level ice on the frequency domain response of floaters

Keijdener, C. (TU Delft Offshore Engineering; Norwegian University of Science and Technology (NTNU))
de Oliveira Barbosa, J.M. (TU Delft Dynamics of Structures)
Metrikine, A. (TU Delft Offshore Engineering; TU Delft Engineering Structures; Norwegian University of Science and Technology (NTNU))

Engineering Structures

2017-11-01

In this paper the effect of a nearby, semi-infinite, level ice sheet on the frequency domain response of a thin, floating, rigid body is studied using a 2D model. The ice is modeled using a dynamic Euler-Bernoulli beam and the finite depth water layer is described with the Laplace equation and the linearized Bernoulli equation. Eigenfunction matching is used to resolve the interface between the ice covered and open water regions. The body is excited by external loads, generating waves. The waves are partially reflected by the ice edge and these reflected waves influence the body's response. It is this influence that this paper focuses on. Below a certain onset frequency the amplitude of the reflected waves is insignificant and consequently the body remains unaffected by the ice. This frequency is only sensitive to the ice thickness with thinner ice resulting in a higher onset frequency. Above the onset frequency the reflected waves cause quasi-standing waves between body and ice. For frequencies at which half the wavelength of the surface wave in the water is approximately an integer multiple of the gap length, the amplitude of the standing waves is greatly amplified. This can result in (anti-)resonance depending on the phasing between the reflected waves and the body's motion.

Frequency domain response
Hydrodynamics
Ice-floater interaction
Level ice

http://resolver.tudelft.nl/uuid:3386dde5-8da0-4531-9178-bd1eb738d54e

https://doi.org/10.1016/j.coldregions.2017.09.004

2019-09-21

0165-232X

Cold Regions Science and Technology, 143, 112-125

Institutional Repository

journal article

© 2017 C. Keijdener, J.M. de Oliveira Barbosa, A. Metrikine