Physically based sub-grid scale modelling for large-eddy simulation to enhance turbulence noise prediction

基于物理的子网格尺度建模，用于大涡模拟，以增强湍流噪声预测

• 批准号: 5405971
• 负责人: Professor Dr.-Ing. Martin Oberlack
• 金额: --
• 依托单位: Laboratoire de Mecanique des Fluides et dAcoustique - UMR 5509
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5405971?language=en
• 关键词: Physically; based; sub; grid; scale

This project is focused on the modelling of sub-grid scale (SGS) models for Large-Eddy Simulation (LES) of turbulence to enhance broad-band noise prediction. The primary objective is to investigate and develop sub-grid scale models for turbulence which allow to capture as many as possible symmetries of the fundamental equations of motion, the Euler and Navier-Stokes equations and the corresponding statistical equations. The rational behind this approach is the observation that in the last century considerable improvement in turbulence modelling has only been achieved if fundamental symmetries and symmetry breaking have been implemented into model equations. These findings apply both for Reynolds averaged as well as for sub-grid scale models as has been shown. Specifically the proposal is threefold: Firstly, the existing SGS-model will be investigated with respect to its symmetries. An established model will be developed further or a new model will be derived along these lines. Secondly, since LES largely suffers from the unsolved nearwall problem, symmetries will be invoked to reduce the computational cost in the vicinity of the wall employing ideas. Thirdly, SGS-models will be investigated with respect to their compatibility with acoustic analogies, such as the Lighthill´s analogy. These analogies have specific symmetries and related analytical properties. Since SGS-models modify acoustic analogies it has to be ensured that the closure assumptions alter the acoustic field as little as possible. SGS-model design should comply with this requirement.

该项目的重点是为湍流的大涡模拟（LES）建立次网格尺度（SGS）模型，以加强宽带噪声预测。主要目标是研究和开发亚网格尺度湍流模型，该模型允许捕获尽可能多的基本运动方程、欧拉方程和纳维尔-斯托克斯方程以及相应的统计方程的对称性。这种方法背后的合理性是观察到，在上个世纪，只有在模型方程中实现了基本对称性和对称性破缺的情况下，湍流模型才有了相当大的改进。这些发现既适用于雷诺平均，也适用于亚网格尺度模型，如已显示的。具体来说，该建议是三重：首先，现有的SGS模型将调查其对称性。将进一步发展已确立的模式，或沿着这些路线推导出一个新的模式。其次，由于大涡模拟在很大程度上受到未解决的近壁问题的影响，对称性将被调用，以减少在壁附近的计算成本。第三，SGS模型将研究它们与声学类比（如莱特希尔类比）的兼容性。这些类比具有特定的对称性和相关的分析性质。由于SGS模型修改声学类比，因此必须确保闭合假设尽可能少地改变声场。SGS模型设计应符合此要求。