ITR/AP(DMS): Numerical Studies of the Nonlinear Interaction Between Turbulent Air Flow and Sea Surface Waves, with Application to Ocean Surface Wave Turbulence

该项目提出了一个数值模型，湍流气流在非线性演变的水面，克服了以前的研究的局限性。高效的模拟气流的计算算法，高效的流体动力学方法来发展海面边界，并行计算技术将结合起来，使统计分析的现实问题，在两个和三个维度的可能。科学可视化方法将用于分析结果，并提高对风和波浪之间的非线性相互作用的理解，这对海面的增长和消散至关重要。将进行研究，以确定在何种条件下，通过包括适当的强迫项，可以将相互作用的复杂系统“解耦”为仅气流模拟或仅流体动力模拟;这些强迫项的形式将与现有的经验和分析模型进行比较，以澄清重要的物理过程。将进行解耦的流体动力学模拟，以研究比耦合空气-水模型中可能存在的问题更大尺度的波浪-波浪能量传递效应，并将获得平衡海面谱的结果形式。还将考虑常用的近似流体动力学模型，以评估其性能，并将使用适用的近似模型外推从数值研究中获得的波浪谱，以包括完整数值模拟中未捕获的破碎波效应。该项目的成果将对全球气候研究、海浪预报以及直接和遥感海洋数据的解释具有重要意义。更一般地说，项目结果将阐明耦合非线性湍流系统中可能发生的重要物理效应。风引起的海面波浪是影响全球气候的基本海气相互作用过程之一。虽然这一主题已经通过物理建模和实验测量进行了广泛的研究，但由于气流和海面波演化中隐含的非线性现象，对所涉及的物理学的理解仍然有限。数值模拟提供了一种提高对该问题复杂相互作用的理解的方法，但直到最近才改进了计算资源，使足够大规模的模拟成为可能。拟议的项目代表了应用数学和工程研究人员之间的跨学科合作。教育工作也是该项目的一个主要目标，包括研究生和本科生教育和研究。该项目的所有参与者将通过算法和代码开发获得信息技术（IT）经验。项目成果将通过会议和期刊出版物以及通过使用万维网与外界交流;项目网络资源也将用于研究小组教授的课程，向学生介绍信息技术研究的科学应用。

The proposed project develops a numerical model for turbulent airflow over nonlinearly evolving water surfaces that overcomes the limitations of previous studies. Efficient computational algorithms for modeling airflow, efficient hydrodynamic methods to evolve the sea surface boundary, and parallel computing techniques will be combined to make statistical analyses of realistic problems in both two and three dimensions possible. Scientific visualization methods will be applied to analyze results and to improve understanding of the nonlinear interactions between wind and waves that are important for sea surface growth and dissipation. Studies will be performed to determine the conditions under which "decoupling" the interacting complex systems into airflow-only or hydrodynamic-only simulations is possible by including appropriate forcing terms; the form of these forcing terms, when applicable, will be compared with existing empirical and analytical models to clarify the important physical processes. Decoupled hydrodynamic-only simulations will be pursued to investigate wave-wave energy transfer effects in larger scale problems than those possible in the coupled air-water model, and resulting forms of the equilibrium sea surface spectrum will be obtained. Commonly applied approximate hydrodynamic models will also be considered to assess their performance, and wave spectra obtained from numerical studies will be extrapolated using applicable approximate models to include breaking-wave effects not captured in the full numerical simulations. Results of the project will be significant for studies of the global climate, sea wave forecasting, and interpretation of direct and remotely sensed oceanographic data. More generally, project results will clarify important physical effects that can occur in a system of coupled nonlinear turbulent systems. The generation of sea surface waves by winds is one of the fundamental air-sea interaction processes that affect the global climate. Although this topic has been studied extensively through both physical modeling and experimental measurements, understanding of the physics involved remains limited due to the nonlinear phenomena implicit in both airflow and sea surface wave evolution. Numerical simulations offer a means to improve understanding of the complex interactions of this problem, but only recently have computing resources improved to make sufficiently large scale simulations possible. The proposed project represents an interdisciplinary collaboration between applied mathematics and engineering researchers. Educational efforts also comprise a principal objective of the project, including graduate and undergraduate education and research. All participants in the project will gain information technology (IT) experience through algorithm and code development. Project results will be communicated to the external community through conference and journal publications and through use of the world-wide-web; project web resources will also be used in classes taught by the research team to introduce students to scientific applications of IT research.