基于DEM-SPH耦合方法的冰区波浪衰减及冰层破碎特性分析

Analysis of Wave Attenuation and Ice Breaking Characteristics Based on DEM-SPH Coupling Method

边缘区海冰-波浪的相互作用过程是影响极地海冰演变规律的重要因素,也是极地船舶与海洋工程中的重要研究内容。为此,该文分别采用扩展多面体离散元方法(DEM)及不可压缩光滑粒子流体动力学方法(SPH)对海冰和波浪的动力过程进行数值分析,进一步建立DEM-SPH耦合模型以模拟海冰在波浪作用下运动和断裂特性,并分析波浪在冰区传播中的衰减过程。基于海冰-海洋相互作用的DEM-SPH耦合模型,详细分析了波高、波浪周期以及冰厚对海冰破坏模式的影响,以及波浪在冰区传播时的衰减规律。计算结果表明:当波高较大或波浪周期较小时,海冰断裂后的尺寸较小,且波浪在冰区中的衰减速率较快;当海冰较薄时,海冰断裂后的尺寸也相对较小,但波浪的衰减速率却相对较慢。以上研究可为海冰-波浪相互作用机理及海冰数值模拟研究提供相关参考依据。

The interaction between sea ice and wave is an important factor to affect the growth of sea ice in polar regions,and is also the major content in polar ship and offshore engineering.In this study,the dilated polyhedral discrete element method(DEM)and the explicit incompressible smoothed particle hydrodynamics(SPH)method are adopted to simulate the dynamics of sea ice and wave,respectively.The DEM-SPH coupling model is established to simulate the movement and breakage of sea ice under the action of waves,and the attenuation process of wave propagation in ice covered regions.Based on the developed DEM-SPH method,the influences of wave height,wave period and ice thickness on the sea ice fracture patterns are compared and analyzed comprehensively,and the attenuation law of waves propagation in ice region is analyzed.From the simulated results,it is found that the size of broken ice rubble is small,and the wave attenuation rate in the ice area is fast under large wave height or short wave period.Moreover,the size of broken ice rubble is small,but the decay rate of the waves is slower under the condition of thin ice thickness.Present study can provide reference to determine the mechanism of ice-wave interaction,and to improve the numerical ice model for polar regions.