CAJ | 학술논문

海冰的断裂、重叠和堆积等离散分布特性广泛地存在于极区和副极区的不同海域，并对海冰的生消、运移过程有着重要影响。针对海冰在不同尺度下的离散分布特点，发展海冰动力过程的离散元方法有助于完善海冰数值模式，提高海冰数值模拟的计算精度。为此，本文针对海冰生消运移过程中的非连续分布和形变特性，发展了适用于海冰动力过程的改进离散元模型（MDEM）。不同于传统离散元方法，该模型将海冰离散为具有一定厚度、尺寸和密集度的圆盘单元。海冰单元设为诸多浮冰块的集合体，其在运移和相互接触碰撞过程中，依照质量守恒发生单元尺寸、密集度和厚度的相应变化。基于海冰离散性和流变性的特点，该模型采用黏弹性接触本构模型计算单元间的作用力，并依据Mohr-Coulomb准则计算海冰法向作用下的塑性变形及切向摩擦力。为验证该模型的可靠性，本文对海冰在规则水域内的运移和堆积过程进行了分析，离散元计算结果与解析值相一致；此外，对旋转风场下海冰漂移规律的模拟进一步验证了本文方法的精确性。在此基础上，对渤海辽东湾的海冰动力过程进行了48 h 数值分析，计算结果与卫星遥感资料和油气作业区的海冰现场监测数据吻合良好。在下一步工作中将考虑海冰离散元模拟中的热力因素影响，发展具有冻结、断裂效应的海冰离散元模型，更精确地模拟海冰动力-热力耦合作用下的生消和运移过程。
해빙적단렬、중첩화퇴적등리산분포특성엄범지존재우겁구화부겁구적불동해역，병대해빙적생소、운이과정유착중요영향。침대해빙재불동척도하적리산분포특점，발전해빙동력과정적리산원방법유조우완선해빙수치모식，제고해빙수치모의적계산정도。위차，본문침대해빙생소운이과정중적비련속분포화형변특성，발전료괄용우해빙동력과정적개진리산원모형（MDEM）。불동우전통리산원방법，해모형장해빙리산위구유일정후도、척촌화밀집도적원반단원。해빙단원설위제다부빙괴적집합체，기재운이화상호접촉팽당과정중，의조질량수항발생단원척촌、밀집도화후도적상응변화。기우해빙리산성화류변성적특점，해모형채용점탄성접촉본구모형계산단원간적작용력，병의거Mohr-Coulomb준칙계산해빙법향작용하적소성변형급절향마찰력。위험증해모형적가고성，본문대해빙재규칙수역내적운이화퇴적과정진행료분석，리산원계산결과여해석치상일치；차외，대선전풍장하해빙표이규률적모의진일보험증료본문방법적정학성。재차기출상，대발해료동만적해빙동력과정진행료48 h 수치분석，계산결과여위성요감자료화유기작업구적해빙현장감측수거문합량호。재하일보공작중장고필해빙리산원모의중적열력인소영향，발전구유동결、단렬효응적해빙리산원모형，경정학지모의해빙동력-열력우합작용하적생소화운이과정。
Breakup,rafting and ridging of ice cover exists widely in the polar and sub-polar regions.These processes affact the growth,vanishing and drifting of sea ice significantly.Considering the discrete distribution of sea ice on various scales,a discrete element model (DEM)should be developed to improve the sea ice numerical model and its computational precission.Thus,a modified discrete element model (MDEM)is established in this study to simulate the sea ice dynamics.Different with the traditional DEM,the ice cover is subdivided into a series of disks with their own characteristics including thickness,velocity,size and concentration,adopting the concept of smoothed particle hydrodynamics (SPH)of sea ice dynamics.Each sea ice element which is an assembly of ice floes changes in its size,concentration and thickness,according to the mass conservation law during drifting and inter-element colli-sions.According to the non-continuous distribution and rheology characteristics of ice cover,the viscous-elastic constitutive model is adopted.And the Mohr-Coulomb friction law is considered to determine the plastic deforma-tion and tangential friction.To assess the reliability of this MDEM for sea ice dynamics,the drifting and ridging of ice cover in a various-width channel is simulated,and the simulated distribution of ice thickness is validated by the analytical solution.The drifting of sea ice in a rotational wind field is also simulated efficiently with high precision. Moreover,the sea ice dynamics in the Bohai Sea is simulated for 48 h.The simulated results match well with the satellite remote images and field observed data.In the future study,the MDEM will be improved by coupling dy-namics and thermodynamics of sea ice.The growth,vanishing and drifting of sea ice will be simulated more accu-rately by consideringthe refrozen effect and breakage feature of ice cover.