Modeling Steep Surface Waves Evolving Under Wind Forcing and Energy Dissipation Due to Wave Breaking

模拟在风力作用下演变的陡峭表面波以及由于波浪破碎导致的能量耗散

• 批准号: 1517456
• 负责人: Wooyoung Choi
• 金额: $ 23.42万
• 依托单位: New Jersey Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517456&HistoricalAwards=false
• 关键词: Modeling; Steep; Surface; Waves; Evolving

Ocean waves play an important role in many areas of science and engineering, notably climatology, meteorology, ocean environment, marine transport, and coastal engineering. They are generated by drawing energy from wind, evolve through nonlinear wave interactions, and are eventually dissipated by wave breaking. When fully developed, ocean waves have wavelengths that span scales from centimeters (capillary waves) to kilometers (tsunami). Computationally resolving models for ocean waves over such a wide range of spatial scales is an enormous challenge, and it is impractical to solve the full hydrodynamic equations over a large surface area of the ocean. These facts have produced an increasing interest in developing a novel and efficient computational tool that can simultaneously treat wind forcing, breaking wave dissipation, and nonlinear wave interactions. This research project aims to contribute to the development of such a tool. Once it is developed, the computational model would be useful for researchers working on physical oceanographic processes and climate change, because the transfer of energy and momentum across the air-sea boundary is fundamental to their work. A graduate student is involved in the project.To predict accurately the evolution of nonlinear surface waves, the investigator and his colleagues develop a reliable and efficient phase-resolving wave model combined with theoretical models of wave breaking and wind-wave interaction. Through numerical simulations using a pseudo-spectral method and controlled laboratory experiments, the predictive capability of the integrated wave model is examined for steep surface waves evolving under wind forcing. To achieve this goal, a robust breaking criterion is first determined though numerical simulations of the wave model and then is confirmed with laboratory experiments. Then, through viscous boundary layer analyses at the deformed surface of steep waves, the viscous energy dissipation rate and the air pressure distribution over the free surface, as well as a criterion of airflow separation, is identified in terms of local flow and wave characteristics. By coupling the results of the boundary layer analyses with measurements of wave breaking and wind-wave interaction experiments, the energy dissipation and wind forcing terms are determined and integrated into the wave prediction model. Finally, the resulting wave model is validated by comparing its numerical solutions with laboratory experiments.

海浪在许多科学和工程领域，尤其是气候学，气象，海洋环境，海洋运输和沿海工程中起着重要作用。 它们是通过从风中汲取能量，通过非线性波相互作用而产生的，并最终通过波浪破裂而消散。 当充分发达时，海浪的波长跨越了从厘米（毛细管）到公里（海啸）的尺度。 在如此广泛的空间尺度上的海浪的计算解析模型是一个巨大的挑战，在大海洋大表面积上求解完整的流体动力方程是不切实际的。 这些事实引起了人们对开发一种新颖有效的计算工具的兴趣，该工具可以同时处理风力强迫，破坏波浪耗散和非线性波相互作用。 该研究项目旨在为这种工具的开发做出贡献。 一旦开发出来，计算模型将对从事物理海洋学过程和气候变化的研究人员有用，因为能量和动量在整个空气界边界上的转移对他们的工作至关重要。 研究生参与了项目。为了准确预测非线性表面波的演变，研究者及其同事开发了可靠，有效的相位分辨波模型，结合了波浪破裂和风波相互作用的理论模型。 通过使用伪谱法和受控实验室实验的数值模拟，检查了综合波模型的预测能力，以了解在风强迫下演变的陡峭表面波。 为了实现这一目标，首先确定了波浪模型的数值模拟，然后通过实验室实验确认了强大的破坏标准。 然后，通过陡峭的波的变形表面进行粘性边界层分析，根据局部流量和波浪特性，确定了粘性的能量耗散速率和自由表面上的气压分布以及气流分离的标准。 通过将边界层分析的结果与波浪断裂和风波相互作用实验的测量结果结合，确定了能量耗散和风力强迫项并将其整合到波浪预测模型中。 最后，通过将其数值解与实验室实验进行比较来验证所得波模型。