全球气候变化下的近岸水沙动力特性及其岸滩响应机制研究

It is devastating that the coastal erosion is serious as extreme waves increase along with global climate changes. Studies of hydrodynamic, sediment transport processes and mechanism of beach profile evolution by extreme waves in inshore region are of not only the vital academic interest but also the comprehensive practical value. The proposed study experimentally analyzes the generalization and simulation techniques of extreme waves hydrodynamic. The laboratory experiments are performed in a wave flume to investigate the extreme waves hydrodynamic characteristic, non-uniform sediment transport, changes of beach profile, scour around the structure, seabed dynamic response and sediment liquefaction. In the mechanism study, the simulation and calculation methods of incipient motion of sediment, bed load transport rate, suspended load carrying capacity and sorting of seabed sand grains under wave, extreme wave as well as wave-current action are obtained respectively. The calculated model for non-uniform sediment transport and forecasted model for beach profile evolution by extreme wave are established. The coupling methods and hybrid theories of multiscale and multiphysics model are optimized. The parallel computing methods and theories for multidimensional mathematical model in multiple spatial and temporal scales are developed. Moreover, the application study presents the 3D Solid-liquid two-phase flow sediment transport mathematical model, the beach profile evolution mathematical model included the non-uniform sediment transport model, the wind-wave-current-sediment transport hybrid multiscale and multiphysics mathematics model. These studies could be beneficial to actual practice.

全球气候变化影响下，极端波况不断出现，对沿海地区构成极大威胁。开展极端波况下近岸地区水沙动力特性及其岸滩响应机制研究，具有重要的学术价值和广泛的实用意义。本研究在机理层面，探讨极端波况动力过程的概化和模拟技术，基于波浪水槽实验研究极端波况下近岸水动力特性，分析海岸非均匀沙运动规律，探求岸滩剖面形态演化、建筑物局部床面变形、海床动力响应机制和泥沙液化规律。在理论层面，建立常浪、极端波况以及波流作用下非均匀沙起动临界流速、推移质输沙率、悬移质挟沙力、床沙交换过程等关键参量的表达式，构造非均匀泥沙输运计算模式和岸滩形态演化预测模式，完善多尺度、多物理场模型之间的耦合和嵌套方法与理论，发展不同时空尺度的多维数学模型并行计算方法与理论。在应用层面，建立三维固液两相流泥沙输运数学模型、基于非均匀沙输移模式的岸滩演变预测数学模型和多尺度、多物理场的风浪流-泥沙运动耦合数学模型，为实际运用奠定基础。

全球气候变化影响下，极端波况不断出现，对沿海地区构成极大威胁。本项目通过实验研究、理论分析和数值模拟，揭示了常浪和极端波况下近岸地区水沙运动机理和沙质岸滩响应机制，建立了非均匀泥沙的非恒定输运计算模式和渗流影响下近岸带冲泻区分段输沙模式。基于区域分解方法和重叠网格技术的理论推导，以及重叠网格内边界的插值算法，构建和完善了多尺度、多物理过程模型之间的耦合和嵌套方法与理论。基于Intel Vtune优化技术，并结合MPI和OpenMP并行计算方法，完善不同时空尺度的多维数学模型并行计算方法与理论。先后建立了三维固液两相流和气液固三相流泥沙输运数学模型、非均匀沙输移模式的岸滩演变预测数学模型、多个多尺度多物理场的风浪流-泥沙运动耦合数学模型，奠定运用的基础。在本项目的资助下发表期刊论文78篇，其中SCI收录20篇、EI收录15篇，1篇入选2015年度“领跑者5000-中国精品科技期刊顶尖学术论文”，获发明专利7项，实用新型专利2项，荣获湖南省科技进步奖二等奖和自然科学奖三等奖。培养博士研究生5名、硕士研究生16名、获湖南省优秀博士学位论文1篇，优秀硕士论文2篇，同时培养了一批人才，共获省级人才称号2人次。