Outdoor Sound Propagation Modelling Across Scales with Uncertainties

该项目设定了以下四个目标：1.研究用于模拟近、中、远距离室外声传播的气象、地面和其他环境数据中的不确定性。通过建模来确定输入模型参数中的不确定性对军用平台发出的声音的模型预测精度的影响。在一个室外声传播通用建模工具(UMTOSP)中开发和集成几个传播模型，该工具在商定的边界内的一系列尺度上都是准确的。为了验证UMTOSP，并展示在计算一系列军用平台产生的声音和存在实际数据不确定性方面的准确性和灵活性。这项工作将建立在声传播模型的最新发展基础上。作为项目成果而开发的新的通用模型将便于用户使用，它将能够从广泛的来源、在具有代表性的环境范围内、在不同的比例尺、在地面以及在低海拔和高海拔计算一个或多个位置的室外声。项目的这一部分将包括对不同传播模型的能力的详细调查，但为了规划项目的目的，预计UMTOSP的基础是：i.计算地面阻抗效应占主导地位时的短程声传播的稳健分析模型(例如[4，5])；2.以能量为基础的边界元方法，研究复杂来源和存在复杂地形和强地面阻抗效应情况下的短程和中程声传播(例如[6])；格林函数，或时间域有限差分，抛物线方程方法(例如，[7，8])，当复杂地形中的中远距离传播受气象条件影响时。这样，模型应包括在近距离、10s至100s米的范围内观察到的影响，例如局部地形或建筑物的存在，中距范围、100s至1000s米的地面阻抗、风况和长距离、1000s至10000s(或更多)米的影响，这些模型(和通用模型)对输入数据中的不确定性的敏感性将使用贝叶斯方法进行研究(例如[9])；这将使我们能够理解当为给定源/接收器几何形状输入不准确或时变的源、气象、地形和地面类型输入数据集时，这些模型所产生的错误。当将这些模型组合在一个UMTOSP中时，这些模型将使我们能够在任何复杂的环境中计算声传播(第一次)，并且在设定的精度极限和传播范围内使用最少的参数。该项目的主要输出将是UMTOSP的软件代码，如果合适，可以用作战术决策辅助的基础。

The proposed project sets the following four objectives:1. To study the uncertainties in the meteorological, ground and other environmentdata which are used to model short, medium and long range outdoor soundpropagation.2. To determine through modelling the influence of uncertainty in the input modelparameters on the accuracy of the model predications for sounds emitted by agiven military platform.3. To develop and integrate several propagation models in one Universal ModellingTool for Outdoor Sound Propagation (UMTOSP) which is accurate over a range ofscales within the agreed bounds.4. To validate the UMTOSP and demonstrate the accuracy and flexibility in terms ofcalculating the sound resulting from a range of military platforms and in thepresence of realistic uncertainty in data.The work will be built on the latest developments in acoustic propagation modelling. Thenew universal model which will be developed as a result of the project will be user-friendlyand it will be able to calculate outdoor sound at one or more positions in range and heightfrom a broad range of sources, in a representative range of environments, at differentscales, on ground and at low and high altitudes.This part of the project will include a detailed investigation into the capabilities of differentpropagation models but, for the purposes of planning the project it is expected that theUMTOSP is based on:i. robust analytical models (e.g. [4,5]) to calculate short range sound propagationwhen the ground impedance effect is dominant;ii. energy-based boundary element methods to study short and middle rangesound propagation from complex sources and in the presence of complexterrain and strong ground impedance effects (e.g. [6]);iii. green's function, or time domain finite differences, parabolic equation methods(e.g. [7,8]) when medium and long range propagation in the presence ofcomplex terrain is affected by the meteorological conditions.In this way, the models should include effects observed at short range, 10s to 100s ofmetres, such as the presence of local topography or buildings, medium range, 100s to 1000s of metres, such as ground impedance, wind conditions, and long range, 1000s to10,000s (and more) of metres, such as temperature and wind profile.The sensitivity of these models (and the universal model) to the uncertainties in the inputdata will be studied using the Bayesian approach (e.g. [9]); this will enable us tounderstand the errors in the calculations these models produce when inaccurate or timevariantsets of source, meteorological, topographical and ground type input data are inputfor a given source / receiver geometry.When combined in one UMTOSP these models will enable us to calculate soundpropagation (for the first time) in an environment of any complexity and with a minimumnumber of parameters within the set accuracy limits and propagation ranges.The main output from the project would be software code for the UMTOSP that could, ifappropriate, be used as the basis for a tactical decision aid.