Laboratory measurements of turbulence and coherent structures on both sides of a wind-driven air-water interface

海气界面上的热量、水分、动量和O2或CO2等气体的交换对包括天气和气候在内的许多现象都至关重要。 近年来，在量化海气通量方面取得了相当大的进展。然而，所涉及的基本过程依赖于海-气界面处的小尺度湍流。这些过程的分辨率很差，海气通量通常是使用现成的参数化，批量变量，如风速。本研究将进行详细的实验室实验，同时测量海气界面两侧的流动，以研究相干流结构以及界面两侧湍流是否耦合以及如何耦合。最终，这项研究的主要社会效益将是改进天气和气候模型，以及改进预测的经济和社会影响，包括渔业，能源工业，商品市场，保险和灾害/威胁准备。在地方一级，该项目将有助于改善本科生和研究生的机会，包括本科生研究教育（REU）计划的夏季奖学金。这项研究产生的新知识将被引入本科生和研究生课程，并通过PI的网站更广泛地传播。学生和其他群体的实验室访问和开放日在PI的实验室进行。这些场合提供了一个机会，让公众了解影响他们的科学问题，并让学生了解海洋科学的职业。该项目建立在测量一种流体（空气或水）中波浪湍流的丰富经验基础上，并通过同时解决两侧问题来扩展它。具体而言，这项研究的目的是：1）进行受控的实验室实验以同时测量空气-水界面两侧的流动，2）评估界面两侧湍流拟序结构之间的耦合和潜在因果关系，3）评估波状界面对湍流通量的贡献和影响，（4）将这些结果与已建立的紊流边界层结果进行比较。预计这些发现将导致对短表面波、湍流、朗缪尔环流、微破碎和分离在海气通量中的作用有更基本的了解。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

The exchange across the air-sea interface of heat, moisture, momentum and gases like O2 or CO2 are critically important for many phenomena including weather and climate. In recent years, considerable progress has been made in quantifying air-sea fluxes. However, the fundamental processes involved rely on small scale turbulence at the air-sea interface. These processes are poorly resolved and air-sea fluxes are generally parametrized using readily available, bulk variables such as wind speed. This study will make detailed laboratory experiments which will simultaneously measure the flows on both sides of the air-sea interface to investigate the coherent flow structures and and whether and how turbulence on either side of the interface is coupled. Ultimately the primary societal benefits of this research will be in improved models of weather and climate and the economic and social impacts of improved forecasts including on fisheries, the energy industry, commodity markets, insurance, and disaster/threat preparedness. At the local level, the project will help improve both undergraduate and graduate opportunities including summer fellowships in Research Education for Undergraduates (REU) programs. New knowledge generated by this research will be introduced into undergraduate and graduate classes, and disseminated more broadly through the PI’s web site. Laboratory visits for schoolchildren and other groups and open houses are conducted at the PI’s laboratory. These occasions provide an opportunity to inform the general public of the scientific issues that affect them and to inform school children about careers in the ocean scienceThis project builds upon extensive experience in measuring wavy turbulent flows in one of the fluids (air or water) and extends it by resolving both sides simultaneously. Specifically, the aims of this research are to: 1) Perform controlled laboratory experiments to measure the flow on both sides of the air-water interface simultaneously, 2) Evaluate the coupling and potential causality between the turbulent coherent structures on both sides on the interface, 3) Assess the contribution and influence of a wavy interface on the turbulent fluxes, and 4) Compare these results with established turbulent boundary layer results. It is expected that the findings will lead to a more fundamental understanding of the role of short surface waves, turbulence, Langmuir circulations, microbreaking and separation in air-sea fluxes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.