Abstract Unexpected releases of hazardous airborne materials may happen in various circumstances, more frequently in accidental situations, less usually due to malicious activities. In all cases, the risk for the population and the rescue team is real and must be evaluated in order to take appropriate protection measures. Numerical models are more and more used in emergency response tools for predicting the atmospheric dispersion of pollutants and estimating impacted areas. Still, flow and dispersion modelling in a built-up environment may be very challenging given the complex geometry and meteorological conditions. Here, we present and evaluate a modelling approach that is a compromise between accuracy and timeliness of the computations. It is based on a 3D Lagrangian Particle Dispersion model driven by 3D flow and turbulence input provided by either a diagnostic mass-consistent model or a model solving the Reynolds-Averaged Navier-Stokes equations. This modelling system has been validated on a panel of experimental test cases from the Cooperation in Science and Technology (COST) Action ES1006 in both idealized and realistic urban mock-ups, wind tunnel and field trials, continuous and puffs releases. The sensitivity of the model to the meteorological input data is assessed. The results are discussed comparing predicted concentrations to measurements. The performances of the modelling system are evaluated through a statistical analysis. They were found to depend on the type of test case, type of release and location of the source in the built-up domain. Results show that the model is compliant with the validation criteria, established in literature for the reference metrics, in the large majority of the test cases. The modelling system proved to be robust enough to be used in the context of emergency response, when fast but still reliable results are needed.

中文翻译：

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在城市环境中使用风洞和现场实验验证拉格朗日粒子弥散模型

摘要 危险空气传播材料的意外释放可能发生在各种情况下，在意外情况下更常见，不太常见的是由于恶意活动。在所有情况下，民众和救援队面临的风险都是真实存在的，必须进行评估以采取适当的保护措施。数值模型越来越多地用于应急响应工具中，用于预测污染物的大气扩散和估计受影响的区域。尽管如此，鉴于复杂的几何形状和气象条件，在建筑环境中进行流动和扩散建模可能非常具有挑战性。在这里，我们提出并评估了一种在计算的准确性和及时性之间进行折衷的建模方法。它基于 3D 拉格朗日粒子弥散模型，该模型由诊断质量一致模型或求解雷诺平均纳维-斯托克斯方程的模型提供的 3D 流动和湍流输入驱动。该建模系统已在科学与技术合作 (COST) Action ES1006 的一组实验测试案例中在理想化和现实化的城市模型、风洞和现场试验、连续和喷气释放中得到验证。评估模型对气象输入数据的敏感性。将预测浓度与测量值进行比较来讨论结果。通过统计分析评估建模系统的性能。发现它们取决于测试用例的类型、发布类型和源在构建域中的位置。结果表明，在大多数测试用例中，该模型符合验证标准，该标准是在文献中为参考指标建立的。当需要快速但仍然可靠的结果时，该建模系统被证明足够强大，可以用于紧急响应环境中。