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| 极地海冰动力过程的多面体离散元方法 |
| A polyhedral discrete element method for sea ice dynamic process in polar regions |
| 投稿时间：2024-01-18 修订日期：2024-03-12 |
| DOI： |
| 中文关键词: 海冰动力学 离散元方法 冰脊模型 海冰断裂 |
| 英文关键词:sea ice dynamics discrete element method ridge model sea ice fracture |
| 基金项目:国家自然科学(52192693, 52192690, 42176241),工信部高性能船舶专项(No. 2021-342) |
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| 中文摘要: |
| 极地海冰影响局部海域的通航条件乃至地质尺度上的气候预测,由于基于连续介质理论的海冰数值模式如网格方法难以应对浮冰尺度的模拟，近年来离散元方法越来越多用于海冰动力学领域。本文使用基于表面网格划分的多面体描述浮冰，通过使用Gilbert-Johnson-Keerthi(GJK)算法以进行初步接触判断并提高计算效率，采用基于能量守恒接触理论确定单元间接触力，由此建立了极地海冰多面体离散元方法。将该方法应用于极地海冰动力过程模拟，并考虑Hopkins提出的冰脊形成导致的海冰间塑性接触力。首先通过两个浮冰间碰撞模拟以验证接触力计算的正确性，再通过对单向均匀风场下浮冰挤压的模拟验证冰脊生成的模拟能力，最后研究冻结强度参数对剪切风场下冰盖断裂和冰脊生成的影响。结果表明：极地海冰多面体离散元方法能够合理地反映地质尺度海冰的动力过程，并且可有效地模拟冰盖线性运动引起的冰隙和冰脊等动力特征。 |
| 英文摘要: |
| Sea ice in polar regions has significant impact on navigational conditions and even climate predictions at geological scales. Addressing the shortcomings of traditional continuum-based grid models for sea ice simulation, the discrete element method (DEM) has emerged as a popular tool in floe dynamics research. In this study, we establish a discrete element method suitable for simulating polar-scale sea ice dynamics. The method employs polyhedrons based on surface triangulation to describe floating ice. The Gilbert-Johnson-Keerthi(GJK) algorithm is employed to enhance computational efficiency. The contact forces between elements are determined based on the energy conservation theory. A bond-fracture model describes the formation of level ice from freezing floes, incorporating plastic forces during the ridge formation process as proposed by Hopkins. Firstly, the accuracy of the contact force calculations is verified through the simulations of collisions between two idealized floes. Subsequently, the capability to simulate ridge formation is validated through the floe field compression under a unidirectional uniform wind. Finally, the influence of bond strength parameters on sea ice fracturing and ridge formation under shear wind conditions is studied. The results indicate that the model effectively captures the dynamics of sea ice on a geological scale and accurately depicts linear kinematic features, such as crevices and ridges, caused by linear motion in ice covers. |
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