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The eigenvalue problem for ice-shelf vibrations: comparison of a full 3-D model with the thin plate approximation.
- Source :
- Earth System Dynamics Discussions; 2015, Vol. 6 Issue 2, p1605-1633, 29p
- Publication Year :
- 2015
-
Abstract
- Ice-shelf forced vibration modelling is performed using a full 3-D finite-difference elastic model, which also takes into account sub-ice seawater flow. The ocean flow in the cavity is described by the wave equation; therefore, ice-shelf flexures result from hydrostatic pressure perturbations in sub-ice seawater layer. Numerical experiments have been carried out for idealized rectangular and trapezoidal ice-shelf geometries. The ice-plate vibrations are modelled for harmonic ingoing pressure perturbations and for high-frequency spectra of the ocean swells. The spectra show distinct resonance peaks, which demonstrate the ability to model a resonant-like motion in the suitable conditions of forcing. The spectra and ice-shelf deformations obtained by the developed full 3-D model are compared with the spectra and the deformations modelled by the thin-plate Holdsworth and Glynn model (1978). The main resonance peaks and ice-shelf deformations in the corresponding modes, derived by the full 3-D model, are in agreement with the peaks and deformations obtained by the Holdsworth and Glynn model. The relative deviation between the eigenvalues (periodicities) in the two compared models is about 10 %. In addition, the full model allows observation of 3-D effects, for instance, the vertical distribution of the stress components in the plate. In particular, the full model reveals an increase in shear stress, which is neglected in the thin-plate approximation, from the terminus towards the grounding zone with a maximum at the grounding line in the case of the considered high-frequency forcing. Thus, the high-frequency forcing can reinforce the tidal impact on the ice-shelf grounding zone causing an ice fracture therein. [ABSTRACT FROM AUTHOR]
- Subjects :
- EIGENVALUES
WAVE equation
HYDROSTATIC pressure
Subjects
Details
- Language :
- English
- ISSN :
- 21904995
- Volume :
- 6
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Earth System Dynamics Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 111574207
- Full Text :
- https://doi.org/10.5194/esdd-6-1605-2015