Collaborative Research: The Physical Biology of Leaves in Wind and Waves

合作研究：风浪中叶子的物理生物学

• 批准号: 1853545
• 负责人: Laura Miller
• 金额: $ 14.97万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-15 至 2021-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1853545&HistoricalAwards=false
• 关键词: Collaborative; Research; Physical; Biology; Leaves

Mathematical, numerical and physical modeling will be applied to reveal the morphological and mechanical adaptations of broad leaves that allow them to survive extreme fluid environments. For example, the principal investigators will determine how the shape and structure of tulip poplar leaves enhance cooling on nearly-stagnant hot summer days while also reducing drag in tropical storm or even hurricane force winds. The models and tools developed in this project will also be applied to determine under what conditions the waving motion of seagrass augments waste removal and enhances photosynthesis. The scientific results of this project will inform the selection of plants that can survive extreme environmental conditions, including low levels of CO2, high temperatures, or strong wind and wave forces. The significance of the proposed also work extends beyond gaining insight into mechanical adaptation of plants in the natural world. The physical principals discovered could drive innovations in the engineering design of flexible structures such as sails, flags, and cables. Furthermore, the computational tools developed in this project will find immediate application in other systems where exchange occurs across flexible structures in air and water, including gas exchange in the lungs, odor capture and pheromone release in a variety of animals, nutrient uptake in the gut, and heat loss in appendages.Flexible plants, fungi, and sessile animals are thought to reconfigure in strong wind and floodwaters to reduce the drag acting upon them. In fast flows, for example, leaves roll up into cone shapes that reduce flutter and drag when compared to paper cutouts of similar shape and flexibility. In light breezes and currents, leaf flutter can be beneficial to heat dissipation and gas exchange. It is not clear how the shape and mechanical structure of broad leaves results in different passive movements across this range of flows. The specific goals of this project are to determine the mechanisms by which 1) single leaves flutter in low winds and flows and roll up into drag reducing shapes in strong flows, 2) leaf flutter enhances heat dissipation and photosynthesis in light winds and flows, and 3) some leaves, such as the touch-me-not, actively reconfigure by changes in turgor pressure initiated by electrical signaling. A combination of numerical simulations and laboratory experiments with real and artificial leaves will be used to quantify both passive and active movements as well as the concentrations of gases and heat. The fluid-structure interaction problem will be solved using the immersed boundary and inviscid vortex sheet methods. A new immersed boundary-style method for modeling the leaf as a source or sink of gases or heat will be developed. Hyperelastic material models will be developed and implemented in the immersed boundary framework to determine how strain-softening or strain-hardening elasticity affects leaf performance.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.

数学，数值和物理建模将用于揭示宽叶的形态和机械适应，使它们能够在极端流体环境中生存。例如，首席研究人员将确定在几乎炎热的夏季，郁金香杨树的形状和结构如何增强冷却，同时还减少了热带风暴甚至飓风风的阻力。该项目中开发的模型和工具也将用于确定在什么条件下，海草的波动增加了废物清除并增强光合作用。该项目的科学结果将告知可以在极端环境条件下生存的植物的选择，包括低水平的二氧化碳，高温或强风和波力。拟议的工作的重要性还扩展到了对自然世界中植物机械适应的深入了解。发现的物理校长可以推动灵活结构的工程设计（例如帆，旗帜和电缆）的创新。此外，该项目开发的计算工具将在其他系统中立即应用，这些系统在空气和水中的柔性结构（包括肺中的气体交换），各种动物的气味捕获和信息素释放，肠道中的养分吸收以及附属物中的热量损失。植物，Fungi和Sessile Diffeers flower flower forne flow and witchfigir interfly和appent off the the肠中的养分损失。例如，在快速流动中，与相似形状和柔韧性的纸张相比，叶片成锥形，从而减少颤动和拖动。在轻微的微风和电流中，叶片颤动可能有益于散热和气体交换。尚不清楚宽叶的形状和机械结构如何导致在这一范围的流中导致不同的被动运动。该项目的具体目标是确定一种机制，即1）单叶在低风和流动中的单叶颤动，然后逐渐变成强大的流动中的拖曳降低形状，2）叶片的颤动可以增强散热和光的光合作用和光合作用，以及3）叶子中的一些叶子，以及一些叶子，例如，触摸 - 触摸 - 触摸 - 毫无用处地通过触摸式的旋转来通过电气压力来进行电动启动，这是由触摸式的发出的启动。数值模拟和实验室实验与真实和人造叶子的结合将用于量化被动和主动运动以及气体和热量的浓度。流体结构相互作用问题将使用浸没的边界和Indiscid Vortex板法解决。将开发一种新的沉浸式边界样式的方法，用于建模叶片作为气体或热量的水源。超弹性材料模型将在沉浸式边界框架中开发和实施，以确定舒适或应变弹性弹性如何影响叶片性能。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛的影响评估的评估来支持的。