BRITE Relaunch: A Physics-Based Simulation Model for Exploring Community Resilience to Wildfires

这项促进工程变革和公平进步的研究理念（BRITE）重新启动奖旨在为野火引起的建筑物着火创建预测计算模型，这是一个日益严重的国家威胁。结构点火受到火焰的辐射以及火焰（即余烬）的热传递的影响。后者直到最近才在文献中引起注意，尽管它是野火引起的结构性点火的主要来源。目前的研究旨在制定和验证一个强大的、基于物理的计算模型，该模型可以模拟结构表面上的着火品牌集合的点火。该模型将根据先前对全尺寸结构和结构部件进行的实验得出。一旦计算模型得到验证，它将被用于研究荒地-城市界面社区的脆弱性。模拟将为正在进行的关于荒地-城市界面社区恢复力的工作提供信息，房主和政策制定者面临着（例如，决定哪些结构升级将对社区恢复力产生最大影响）。该研究计划包括一个使用概率多相欧拉方法的野火火种运输模型，与现有的专注于拉格朗日粒子跟踪的方法相比，该模型为基于社区的模拟提供了更好的计算效率和可扩展性。此外，该方法还利用离散元方法探讨了在屋顶和墙壁的冲击下，燃烧器的断裂和质量损失。这种离散元方法的新应用也将具有显著的优势，包括与固体力学耦合的传热传质的新公式。该模型将根据先前的结构部件和系统实验进行验证。该高保真计算模型有望产生新的认识，并对野火引起的结构火灾进行更准确的预测，从而提高社区的恢复能力，减少灾难性野火造成的损失。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

This Boosting Research Ideas for Transformative and Equitable Advances in Engineering (BRITE) Relaunch award seeks to create a predictive computational model for the ignition of buildings due to wildfires, which are a growing national threat. Structural ignition is affected by radiation from the flames as well as heat transfer from firebrands (i.e., embers). The latter has only recently gained attention in the literature despite being a leading source of structural ignitions due to wildfires. The present research seeks to formulate and validate a robust, physics-based computational model that simulates ignition from collections of firebrands on structural surfaces. The model will be informed by prior experiments on full-scale structures and structural components subjected to firebrand showers. Once the computational model is validated, it will be used to study the vulnerability of communities at the wildland-urban interface. The simulations will inform ongoing work on community resilience at the wildland-urban interface, where homeowners and policymakers are faced with (e.g., deciding what structural upgrades will have the greatest impact on community resilience).The research plan involves a model for the transport of firebrands from the wildfire using a probabilistic multiphase Eulerian approach that offers better computational efficiency and scalability for community-based simulations when compared to existing methods that focus on Lagrangian particle tracking. In addition, the approach explores the fracture and mass loss of firebrands under impact with roofs and walls using the discrete element method. This new application of the discrete element method will have significant advantages as well, including new formulations for heat and mass transfer coupled with solid mechanics. The model will be validated against prior experiments on structural components and systems. The high-fidelity computational model is expected to yield new understanding and give more accurate predictions of structural ignitions due to wildfire, leading to greater community resilience and fewer losses in the event of catastrophic wildfire.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.