CAREER: Mechanistic Modeling of Turbulent Bubbly Flows in the Ocean Surface Boundary Layer

职业：海洋表面边界层湍流气泡流的机理建模

• 批准号: 1945502
• 负责人: Junhong Liang
• 金额: $ 47.22万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945502&HistoricalAwards=false
• 关键词: CAREER; Mechanistic; Modeling; Turbulent; Bubbly; CAREER; Mechanistic; Modeling; Turbulent; Bubbly

Oceanic bubbles play important roles in upper ocean dynamics and in air-sea gas exchange. This project will study their distribution near the ocean surface and their interaction with turbulence, and improve the representation in numerical models of their impact on the exchange of gases between the ocean and atmosphere. Randomly-distributed breaking waves and small- scale currents are two ubiquitous processes in the upper ocean. Their roles on bubble dynamics and bubble-mediated air-sea gas transfer have never been studied due likely to the challenges in observing and modeling of gas bubbles in those two dynamical processes. Utilizing state-of-the-art computer models that simulate the co-evolution of the two dynamical processes, gas bubbles, and dissolved gases based on first principles, this study will advance our fundamental understanding of bubble dynamics in the upper ocean and its coupling with upper ocean dynamics. It will also improve representation of bubble-mediated gas fluxes in computer models. This research improves our understanding of the earth system in terms of both upper ocean dynamics and ocean biogeochemical cycling. It will reduce uncertainties in the modeling and budget estimate of climatically and environmentally important soluble gases such as oxygen and carbon dioxide. It will also improve our ability to use dissolved gases such as oxygen, nitrogen and argon, whose dissolved concentrations are affected by bubbles, as tracers for biogeochemical processes. The anticipated results can also be applied to the understanding and prediction of buoyant marine pollutants including spilled oil and marine plastics. Therefore, the study will improve our capability to predict marine environment and climatic changes, and will provide better scientific basis for decision makers in politics and industry on a range of issues including climate, environment, fisheries, energy and marine pollution mitigation. The educational component of the CAREER project includes developing a two-day mini-workshop for K-12 teachers, and creating an interactive webpage for hand-on ocean modelling activities that will be used in a summer camp and a general education class for non-STEM students that the PI has been teaching. The purposes of the educational activities are to attract local middle and high school students to the field of oceanography, to raise the awareness of the importance of the ocean among students and the general public, and to further enrich the curriculum for physical oceanography at LSU.The primary research objectives of this project are to better understand the distribution of gas bubbles and the coupling between bubbles and oceanic turbulence in the ocean surface boundary layer, and to more accurately parameterize bubble-mediated air-sea gas flux. Two hypotheses, identified based on previous studies and preliminary results, will be tested: (1) Stochastic breaking waves affect bubble trajectories and bubble-mediated gas flux through altering ocean boundary layer turbulence and generating bubbles at downwelling currents; and (2) Submesoscale currents alter bubble trajectories and bubble-mediated gas flux via interaction with ocean boundary layer turbulence. These hypotheses will be tested using a state-of-the-art large eddy simulation modeling framework. The coupled modeling framework consists of a Large Eddy Simulation (LES) model that simulates the ocean surface boundary layer turbulence with the impact of stochastically distributed breaking waves, a Lagrangian particle model that tracks bubbles and bubble properties, and an Eulerian concentration model for dissolved gases.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.

海洋气泡在上海动力学和气海气交换中起着重要作用。该项目将研究其在海面附近的分布以及与湍流的相互作用，并改善其影响其对海洋和大气之间气体交换的数值模型的表示。随机分布的断裂波和小规模电流是上海中的两个无处不在的过程。由于在这两个动态过程中观察和建模气体气泡的挑战，因此从未研究过它们在气泡动力学和气泡介导的气海气体转移中的作用。利用最新的计算机模型模拟了基于第一原理的两个动力学过程，气泡和溶解气体的共同进化，这项研究将提高我们对上海中气泡动力学及其与上海动力学耦合的基本了解。它还将改善计算机模型中气泡介导的气通量的表示。这项研究从上海动力学和海洋生物地球化学循环方面提高了我们对地球系统的理解。它将减少在气候和环境上重要的可溶性气体（例如氧气和二氧化碳）的建模和预算估计中的不确定性。它还将提高我们使用溶解气体（例如氧，氮和氩气）的溶解气体的能力，氮气和氩气会受到气泡的影响，作为生物地球化学过程的示踪剂。预期的结果也可以应用于对浮动油和海洋塑料在内的浮力海洋污染物的理解和预测。因此，这项研究将提高我们预测海洋环境和气候变化的能力，并将为政治和行业的决策者提供更好的科学基础，包括气候，环境，渔业，能源和海洋污染的一系列问题。职业项目的教育组成部分包括为K-12教师开发为期两天的迷你工作工厂，以及为手工训练营的手工训练营和非茎学生的通识教育课程创建一个交互式网页，PI一直在教书。 The purposes of the educational activities are to attract local middle and high school students to the field of oceanography, to raise the awareness of the importance of the ocean among students and the general public, and to further enrich the curriculum for physical oceanography at LSU.The primary research objectives of this project are to better understand the distribution of gas bubbles and the coupling between bubbles and oceanic turbulence in the ocean surface boundary layer, and to more accurately parameterize bubble-mediated气海气通量。将测试基于先前的研究和初步结果的两个假设：（1）随机断裂波影响气泡轨迹和气泡介导的气体通量，通过改变海洋边界层的湍流并在下降流处产生气泡； （2）通过与海洋边界层湍流相互作用来改变气泡轨迹和气泡介导的气体通量。这些假设将使用最先进的大涡模型建模框架进行测试。耦合的建模框架由大型涡流模拟（LES）模型组成，该模型通过随机分布的破裂波的影响模拟海面边界层的湍流，一个跟踪气泡和气泡特性的Lagrangian粒子模型，以及通过eulerian浓缩模型来依靠NSF的基础，并以eulelian的浓度为基础。和更广泛的影响审查标准。