Xu, Boyang2023-01-262023-01-262022https://udspace.udel.edu/handle/19716/32168The problem of wave-ice interactions in the marginal ice zone is investigated. Two principal mechanisms: scattering by ice floes and dissipative processes, may cause the wave spectrum attenuation. These two mechanisms are studied both theoretically and numerically. ☐ First, a two-layer poroelastic model for linear gravity waves propagating in ice-covered seas is considered. Numerical solutions of the corresponding dispersion relation are obtained. Extensive tests against both laboratory experiments and field observations are performed to assess this model's ability at describing wave attenuation in various types of sea ice. A detailed comparison with other existing viscoelastic theories is also presented. For this poroelastic system, the range of estimated rheological parameters, such as shear modulus and kinematic viscosity, turns out to be relatively narrow in orders of magnitude over all the cases considered. Instead of monotonically increasing with frequencies, the measured apparent attenuation rate from the Arctic Ocean peaks at an intermediate frequency. This model is able to reasonably reproduce the "roll-over" of attenuation rate as a function of frequency. ☐ Second, phase-resolved numerical simulations are performed to investigate the scattering process from a nonlinear and time-dependent viewpoint. Spatial distributions of ice floes can be directly specified in the numerical model. Various wave regimes and floe configurations are considered in the absence of dissipative effects. The attenuation rate is obtained by computing the wave spectrum and least-squares fitting for each set of parameter values. Comparison with field data suggests that our numerical results can also capture the roll-over effect. Nonlinear interactions are shown to play an important role in the roll-over development.DissipationModelingNumerical analysisScatteringWaveThesis1365636102https://doi.org/10.58088/vwxv-fq952022-09-21en