Abstract Unraveling the physics of fire-wind interaction has long been a subject of interest. Among all the physics involved, enhancement of wind by fire deserves great attention due to its potential effects on building structures downstream of the fire source in bushfire attack events. Predominantly, two contributing factors determine the extent to which wind is enhanced by fire: freestream wind velocity and fire intensity. This study employs Large-Eddy Simulation (LES) to fundamentally investigate the combined effects of freestream wind velocity and fire intensity on fire-wind enhancement. An added module was implemented to an open-source transient fire solver in order to analyze the effects of freestream wind velocity and fire intensity based on the analysis of interactions between momentum and fire-induced buoyancy forces. Simulations are performed for parametric combinations of wind velocity and fire intensity. The LES results demonstrate that the normalized maximum wind enhancement increases with a reduction of freestream wind velocity and an increase in fire intensity. The non-dimensional Froude number, Fr, and normalized fire intensity, I*, were employed to quantify the effects of freestream wind velocity and fire intensity, respectively. A correlation was developed to determine the maximum wind enhancement as a function of Fr and I*. The location corresponding to maximum wind enhancement occurs further downstream of the fire source as freestream wind velocity or fire intensity increases. A correlation based on the Fr number and I* was developed for the location at which maximum wind enhancement occurs. Furthermore, the concept of wind enhancement plume line was defined as a line along which the local wind enhancement occurs at a given longitudinal location downstream of the fire source, for which a correlation was also developed. Moreover, a gradual decaying trend is observed in wind enhancement after reaching a peak along the wind enhancement plume line in all simulation scenarios for which a correlation was also developed as a function normalized longitudinal direction.

中文翻译：

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基于LES模拟的火风增强流动特性相关性

摘要 解开火-风相互作用的物理学长期以来一直是一个令人感兴趣的课题。在所有涉及的物理学中，火对风的增强值得高度关注，因为它在丛林大火袭击事件中对火源下游的建筑结构有潜在影响。主要有两个因素决定了火灾增强风的程度：自由流风速和火灾强度。本研究采用大涡模拟 (LES) 从根本上研究自由流风速和火灾强度对火风增强的综合影响。在开源瞬态火灾求解器中实施了一个附加模块，以便基于对动量和火灾引起的浮力之间相互作用的分析来分析自由流风速和火灾强度的影响。对风速和火灾强度的参数组合进行模拟。LES 结果表明，归一化的最大风力增强随着自由流风速的降低和火灾强度的增加而增加。无量纲弗劳德数 Fr 和归一化火灾强度 I* 分别用于量化自由流风速和火灾强度的影响。开发了一种相关性来确定作为 Fr 和 I* 函数的最大风力增强。随着自由流风速或火灾强度的增加，对应于最大风力增强的位置发生在火源的更下游。建立了基于 Fr 数和 I* 的相关性，用于出现最大风增强的位置。此外，风增强羽流线的概念被定义为在火源下游给定纵向位置发生局部风增强的线，为此还开发了相关性。此外，在所有模拟场景中，在沿风增强羽流线达到峰值后，在风增强中观察到逐渐衰减的趋势，其中相关性也被开发为函数归一化纵向。