【作者】 王刚；

【导师】 吕和祥； 岳前进； 季顺迎；

【作者基本信息】 大连理工大学 ， 固体力学， 2007， 博士

【摘要】 海冰运动是全球水循环的一个重要环节，对全球的气候变化和寒区海上经济活动都有重要的影响。海冰动力学主要研究海冰在海洋、大气的动力强迫下的运动变化、动量传输及其断裂、重叠和堆积等动力学特征。其中表征海冰内部相互作用的本构模型一直是提高海冰动力学数值模拟精度的关键内容。本文在国家自然科学基金项目“中小尺度海冰动力学的本构模型及数值方法研究”(批准号：40206004)的资助下，对目前海冰动力学本构模型的研究成果进行了系统地总结和分析，在此基础上，根据海冰动力学尺度的定义，以渤海海冰为主要研究对象，针对渤海海冰的特点及其油气开发的需要，对中小尺度下的海冰动力学本构模型进行了研究。系统地介绍了海冰对气候和经济活动的影响，详细地回顾了海冰动力学本构模型的发展历程，并指出了海冰动力学本构模型研究存在的问题和不足。在此基础上，结合渤海海冰的特点，介绍了本论文进行的主要工作。对海冰动力学数值模拟常用的数值方法，如有限差分法、质点网格法和光滑质点流体动力学方法、物质点法等，进行了系统的总结和分析。针对渤海海冰的特点，详细地介绍了本文数值模拟所采用的光滑质点流体动力学方法的基本原理，并建立了适用于本文粘弹-塑性海冰动力学本构模型的控制方程。建立了适用于中小尺度海冰数值模拟的粘弹-塑性海冰动力学本构模型。在该本构模型中，采用Kelvin-Vogit粘弹性模型来描述小应变及小应变率下海冰非屈服状态下的力学行为；分别采用Drucker-Prager屈服准则和考虑中间主应力效应的广义双剪应力屈服准则来判别海冰的屈服状态：屈服后采用相关联的正则流动法则，同时考虑了海冰厚度影响下静水压力对海冰本构模型的影响。采用规则区域海冰堆积过程、渤海动力演化过程以及JZ20-2海域海冰参数演化过程对本构模型的可靠性和适用性进行了数值验证。对影响海冰生消的热力要素进行了分析，并将其引入到光滑质点流体动力学海冰动力模式中，发展了一个基于SPH数值方法的海冰热力-动力数值模式。采用该热力-动力模式对渤海海冰进行了48h的数值模拟，同时对JZ20-2海域的冰厚变化、冰内温度场分布以及热力因素变化特性进行了讨论。对冰脊形成过程中，粘结力的产生机理以及各种影响因素进行了初步解释。考虑三种不同情况下的海冰堆积过程，将粘结力分别设为初始冰厚、当前堆积冰厚和海冰温盐的函数，分别建立了海冰粘结力的理论表达式，并将其应用到Mohr-Coulomb屈服准则中，建立了考虑粘结力影响的粘弹-塑性海冰动力学本构模型。应用该本构模型对海冰堆积过程进行了数值试验，得到了不同粘结力情况下海冰厚度的分布规律，并讨论了相关参数对海冰堆积过程的影响；通过数值试验结果验证了粘结力影响下本构模型的可靠性。在此基础上，将考虑粘结力影响的粘弹塑性海冰动力学本构模型在渤海海冰数值模拟中进行了初步应用。更多还原

【Abstract】 The sea ice motion is an important portion of the global water circulate, which has obvious influence on the global climate change and the marine activities in cold regions. The sea ice dynamics mainly includes the sea ice motion, breakup, rafting and ridging under the driving of ocean and atmosphere. The constitutive model, which describes the internal action of ice cover, is the key point to improve the accuracy of sea ice simulation.This paper is supported by the National Science Foundation of China (Grant No. 40206004). The state-of-art of the constitutive model of sea ice dynamics was summarized and analyzed in this paper firstly. Combined with dynamical characteristics and engineering demands of oil/gas exploitation in the Bohai sea ice, and the disadvantages of constitutive models for sea ice dynamics under meso-small scale was discussed in details.The influences on the climate and economy of sea ice were presented in details, and the developing process of constitutive model for sea ice dynamics was reviewed also. The open problems and shortcomings in the constitutive model of sea ice dynamics were pointed out. Based on the discussions above, the main studies of this thesis were introduced considering the sea ice characteristics in the Bohai Sea under meso-small scale.The series of numerical method as Finite Different Method (FDM), Particle-In-Cell (PIC). Smoothed Particle Hydrodynamics (SPH) and Material Point Method (MPM) et al were introduced. Considering characteristic of the Bohai Sea, the SPH basic theory was introduced detailed. Based on the SPH theory, the moment equation and viscoelastic-plastic constitutive model of sea ice dynamics were described.The viscoelastic-plastic constitutive model for sea ice dynamics was established under meso-small scale. In this model, the Kelvin-Vogit viscoelastic model is adopted before ice yielding. And the Drucker-Prager yield criterion and the generalized twin shear stress yield criterion considering the effect of intermediate principal stress was adopted, respectively. In the yielding state, the associated normal flow rule is used. The effect of hydrostatic pressure was also considered in this model. Using the VEP model above, some numerical simulations were carried out to model the sea ice ridging process in an idealized rectangular basin. Moreover, the sea ice numerical simulation of Bohai Sea, and the sea ice parameter evolution process in the JZ20-2 ice field wcre also simulated. The reliability of this viscoelastic-plastic model was validated with these numerical simulation tests. Considering of the influences of sea ice thermodynamic factors on ice conditions, a sea ice thermodynamic-dynamic model was established based on the SPH model for sea ice dynamics. With this present sea ice model, the sea ice of Bohai Sea was simulated in 48 hours. The ice thickness, temperature in vertical direction of sea ice and the other thermodynamic factors were also discussed.The mechanism of cohesion in the generation of ice rubble and ice ridging, the main factors arc demonstrated and analyzed elementarily. Considering three sea ice ridging process. the cohesion is set up as a function of initial ice thickness, total ice thickness, temperature and salinity, respectively. The theoretic expressions of sea ice cohesion were determined and to be introduced into the Mohr-Coulomb yield criterion. The viscoelastic-plastic constitutive model of sea ice dynamics was established considering the cohesion influence here. Meanwhile, the analytical solution was determined under the different conditions. The numerical tests were carried out into sea ice ridging process with this constitutive model. The distributions of sea ice thickness were obtained and the influence of correlative parameters on correlative was discussed.更多还原