海啸力学及其在南中国海的应用

This project will focus on the hydrodynamic problems associated with tsunamis in the whole life span, reveal the mechanism of tsunami disasters and develop tsunami modelling and prediction methods. The framework of tsunami mechanics consisting of theoretical analysis, modelling methods and applied technologies is established. . An integrated method of field survey data, theoretical solution, numerical simulation and physical model test is developed to the studies on tsunami science and its applications. The observed and field surveyed data of 2004 Indian Ocean Tsunami and 2011 Tohoku Tsunami are collected and analyzed comprehensively to identify the hydrodynamic characteristics of tsunamis in terms of wave profile and velocity field, the response of coastal structures and coastal morphology. . The fully nonlinear and highly dispersive water wave model is developed to simulate the generation, deformation, run-up and inundation of tsunamis. More effects are paid to improve the tsunami source model of basic source parameters and the time varying bottom deformation for the generation of tsunami. Regarding the propagation and deformation of tsunami in open ocean and continental shelf, the nonlinearity and dispersion effects of waves are evaluated to research into the mechanism of the different wave profiles of tsunami observed in 2004 Indian Ocean tsunami and 2011 Tohoku tsunami. The effects of the bottom roughness and the morphological profiles are considered in developing the theoretical and numerical approaches in modelling runup and rundown processes of tsunami on beaches. Modelling methods of tsunami are validated in terms of the hydrodynamic processes of tsunami in its whole life span based on the field survey data and physical model tests. . A hybrid approach of generating transient tsunamis with different wave profiles is developed to simulate the tsunami waves of different scales. In order to reveal the mechanism of the effects of coral reef and typical coastal topography and morphology on wave profile and velocity field, the hydrodynamic loads acting on breakwaters, sea dikes and buildings, well controlled physical model investigations on tsunami runup, inundation and impacts on coastal structures are carried out. Several benchmark tests for model validation are established. . The potential tsunami and the worst extreme tsunami generated by the earthquake in the Manila trench are simulated to evaluate the tsunami risk and to establish the early warning system for the South China Sea region. Based on the measured date by the buoys and numerical computation, the inversion approach is developed to establish the tsunami early warning method with optimized locations of buoys and parallelized numerical model. Scenarios of tsunamis induced by earthquakes with different magnitudes are provided and analyzed. Hydrodynamic loads acting on offshore structures in the coral reefs regions at the potential tsunami conditions are studied theoretically and experimentally. Tsunami inundation maps in terms of tsunami arrival time, tsunami height, maximum velocity and inundation depth for the South China Sea region are proposed to provide tsunami risk information for coastal managements.

本项目旨在系统深入地研究海啸全生命周期的关键力学问题，揭示海啸成灾机理，突破海啸模拟技术，形成海啸力学的基本理论、模拟方法和应用技术体系。采用观测资料的综合分析、理论分析、数值模拟和物理实验相结合的方法研究海啸的水动力学特性与预警方法。重点收集2004印度洋海啸和2011日本东北海啸等典型海啸的各类观测资料，综合分析海啸传播和成灾特征。发展完全非线性色散水波理论，建立海啸生成、演化、爬高和淹没过程的理论分析方法和数值模型，实现海啸全生命周期的数值模拟。突破具有非线性和瞬态性特征的近海典型海啸波的室内水池模拟技术，实现海啸淹没过程及其对海岸结构物作用的水池模型实验。研究南中国海马尼拉海沟潜在地震海啸的水动力学特征、近岛礁海洋结构物的水动力载荷和海啸预警新方法，建立南中国海区域海啸快速预警方法和海啸淹没图，为南中国海周边国家和地区的海啸防灾减灾提供科学依据和强有力的技术支撑。

本项目针对海啸生成、传播、爬高、淹没以及对海岸结构物的作用等问题，研究海啸全生命周期的关键力学问题，揭示海啸成灾机理，突破海啸模拟技术，形成海啸力学的基本理论、模拟方法和应用技术体系。主要研究内容包括：在典型地震海啸震源参数和成灾特征研究方面，发展了考虑时间过程的海啸震源模型，构建了南中海啸马尼拉断裂带的基本参数集和潜在极端地震的震源模型；建立了可模拟地震激发海底地形变形过程的海啸生成力学模型，揭示了非线性和色散效应对海啸传播与变形的影响规律，模拟了海啸传至极浅水地区出现非破碎涌波和孤立波分裂的复杂波动现象；建立了近海海啸水池，发展了实验室水池内生成典型海啸波的模拟方法，实现了非破碎涌波、多个孤立波、N-波等典型海啸波的水池模拟；建立了南中国海马尼拉海沟断裂带地震激发海啸的数学模型，实现了典型岛屿与海岸地区海啸淹没过程和流场的数值模拟，获得了极端海啸到达南中国海沿海国家和地区近海不同等深线处的时间、最大波高以及波形特征；发展了基于多浮标观测和数值模拟反演的南中海海啸预警方法，建立了利用浮标监测得到的波面信息确定断裂带各单元板块滑移量的反演方法，分析比较了单元分块方式和浮标位置对反演结果的影响，探讨浮标位置的优化方案；开展了类海啸波对海底、淹没平板等典型结构作用的物理模型实验，建立了基于双目成像的局部三维波面测量技术；应用建立的海啸数值模型，开展了我国南海大型人工岛工程的海啸风险评估。