Research On The Hydroelastic Characteristics Of Ice Floes In Waves

As the global climate changes,there is some evidence shows that the overall extent of sea ice cover in the Arctic is decreasing,making it possible to open Arctic shipping lanes and develop natural resources on a large scale.The transition between open sea and ice covered water is known as the marginal ice zone(MIZ),which is also most directedly affected by waves.the structure of the MIZ is mainly determined by waves and ice interactions.Mastering the law of the interactions between sea ice and waves in the MIZ is of great guiding significance for correct understanding of the wave propagation characteristics and rational development of the Arctic.Firstly,the interactions between small-medium-scale ice floe and waves are studied in this paper,including two-dimensional rigid multiple ice floes and wave interactions as well as three-dimensional rigid single ice floe and waves interactions.In this part,the numerical wave tank is established based on computational fluid mechanics technology.The waves are generated by imposing a specified velocity condition on the inlet boundary.Finite volume method is employed to solve fluid governing equation,and the free surface is captured by Volume of Fluid method.The ice floe motion is separately modeled by dynamic grid and overset grid.Then,the research is extended to the two way fluid-structure interaction between three-dimensional large-scale elastic ice floes and waves.Finite volume method and finite element method are respectively utilized to discrete fluid domain and ice domain.A mapping interface at the junction of the fluid domain and the ice floes domain is created to perform data mapping by shape function interpolation method and the least square method.The effect of overwash phenomenon on ice floe motion and wave motion is studied thoroughly.The main conclusions are as follows:(1)By analyzing multiple rigid ice floes motion under wave action,it is found that due to the interaction between multiple ice floes and waves and the mutual interference of multiple ice floes,ice floes have shielding effect and attenuation effect on waves.With the increase of the amount of ice floes,the motion amplitude of the middle ice floe is correspondingly smaller.The farther the narrow gap between ice floes away from the wave entrance,the more gentle the wave motion in the narrow gap.The motion amplitude of ice floes is significantly reduced because of the effect of the overwash.At the same time,as thenumber of ice floes increases,the wave overwash phenomenon on the middle ice floes weakens,and the difference in the amplitude of ice floes gradually decreases.(2)The simulation results of the interaction between single rigid ice floe and waves shows that in the case of small wavelength,the overwash phenomenon is more prominent.The overwash phenomenon has a significant suppression effect on heave and pitch of ice floes.As the ovewash phenomenon becomes stronger,the effect of suppression on ice floes motion is stronger.(3)In the study of the hydroelastic response of three-dimensional large-scale elastic ice floes under the action of waves,it is found that the shape of ice floes has a great influence on its own deformation and the surrounding wave field.As the ice length along the wave propagation is longer,the ice floe has the larger contact area with the incident wave,resulting in a greater reflection effect floe on the wave.As the ice length perpendicular the wave propagation is longer,the wave overwash phenomenon and the vertical deformation of the ice floes become more severe,which attenuates the incident wave to a greater extent.Due to the shielding effect and scattering effect of ice floes on the waves,the transmitted waves near the trailing edge of the ice floes are much smaller than the transmitted waves away from the trailing edge of the ice floes.