CAREER: Transport properties and morphology associated with bursting-bubble induced jetting phenomena

PI：伯德，詹姆士建议编号：1351466这项职业计划的重点是了解气泡破裂时产生气雾滴的物理机制。了解亚微米气溶胶形成背后的物理原理在许多工程应用中都很重要，从涡轮机腐蚀到呼吸系统死亡的扩散，因为它们在大气中的停留时间可能在几周左右。智慧价值：当气泡破裂时，会形成一组液滴，这些液滴会分解成其他较小的液滴，其中较大的液滴会进一步分解，从而形成液滴大小的层次结构。最终，形成亚微米气溶胶液滴，这是目前的流体动力学模型无法预测的，因为造成它们形成的主要物理机制尚不清楚。这项提议的目标是探索三个概念，即从小的破裂气泡中喷出的水滴如何解释观察到的亚微米气溶胶。一种概念是，将毫米级气泡的大小与其产生的喷射液滴的大小联系起来的经验公式可能不适用于微米级的气泡。另一个概念是，当产生较大的液滴时，卫星和次卫星液滴可能会形成，而这些较小的液滴可能解释了无法解释的亚微米气溶胶。最后一个概念是，较大的气泡诱导的喷流可能与较小的喷流液滴或卫星液滴相结合，并将较小的液滴推进到粘性下层之外。PI将使用直接高速观测、数值模拟和适当确定维度的实验模型来探索和评估这些想法。广泛影响：拟议工作的结果可以找到具有重大经济和社会影响的重要应用，例如避免在海洋环境中运行的传感器和发动机中因盐气溶胶造成的腐蚀。在当地规模上的其他应用包括对气雾化病原体(如赤潮毒素)的空气传播通量进行建模，以做出更好的公共政策决策，如关闭哪些海滩。在全球范围内，更好地了解气溶胶的产生对于减少全球气候模型中的不确定性是必要的，这将使政策制定者能够更好地评估地球工程缓解策略的风险和回报，例如故意向大气中注入大量硫磺颗粒，以期对抗温室气体的变暖影响。该提案还包括与研究项目相辅相成的外展和教育活动。提议为职前早期教育教师举办讲习班，并为经验丰富的在职小学和学前教育教师提供密集的实验室沉浸体验。最后，该提案包括与波士顿科学博物馆合作开发新的科学模块，旨在增加儿童与父母之间的科学参与。

PI: Bird, JamesProposal Number: 1351466The proposed CAREER project is focused on understanding the physic al mechanism of the generation of aerosol droplets as bubbles burst. Understanding the physics behind submicron aerosol formation is important in a host of engineering applications ranging from turbine corrosion to the dispersion of respiratory deceases, since their residence time in the atmosphere can be on the order of weeks. Intellectual Merit:When a bubble bursts, a set of droplets is formed and these droplets break into other smaller droplets, the larger of which break up further creating a hierarchy of droplet sizes. Ultimately, submicron aerosol droplets are formed that are not predicted with current fluid dynamic models, since the primary physical mechanism responsible for their formation is unknown. The goal of this proposal is to explore three concepts on how jet drops from small bursting bubbles may account for observed submicron aerosols. One concept is that the empirical formulas that relate the size of millimeter bubbles to the size of jet drops that they produce may not be valid for micron-scale bubbles. Another concept is that satellite and sub-satellite droplets may develop when larger droplets are produced, and that these smaller droplets may account for the unexplained submicron aerosols. The final concept is that larger bubble-induced jets may couple with smaller jet drops or satellite drops and propel the smaller drops beyond the viscous sublayer. The PI will explore and evaluate these ideas using direct highspeed observations, numerical simulations, and appropriately dimensionalized experimental models.Broader Impacts:Results from the proposed work can find important applications with significant economic and societal impact, for example avoiding corrosion due to salt aerosols in sensors and engines operating in marine environments. Other applications on a local scale include modeling the airborne flux of aerosolized pathogens, such as bevotoxins from red tides to make better public policy decisions, such as which beaches to close. On a global scale, a better understanding of aerosol production is necessary to reduce uncertainty in global climate models, and will allow policy makers to better assess the risks and rewards of geoengineering mitigation strategies, such as deliberately injecting large amounts of sulfur particulates in to the atmosphere in hopes to counter the warming effects of greenhouse gases.The proposal also includes outreach and education activities that are complementary to the research project. It is proposed to develop workshops for pre-service Early Childhood Education teachers and intensive laboratory immersion experiences for seasoned in-service elementary and preschool teachers. Finally, the proposal includes a partnership with the Boston Museum of Science to develop new science modules that aim to increase scientific engagement between children and their parents.