Numerical simulation of turbulent flows in complex geometries using the CVS approach based on orthonormal wavelet decomposition

使用基于正交小波分解的 CVS 方法对复杂几何形状的湍流进行数值模拟

• 批准号: 5405071
• 负责人: Professor Dr.-Ing. Henning Bockhorn
• 金额: --
• 依托单位: Centre de Mathématiques et dInformatique
• 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 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5405071?language=en
• 关键词: Numerical; simulation; turbulent; flows; complex

Turbulent reacting flows are characterized by their large range of active temporal and spatial scales. In most cases a decoupling of the small from the large spatial scales and the slow from the fast temporal scales cannot be achieved. Multiscale representations, such as wavelet bases, allow to circumvent this obstruction and are, therefore, promising for modelling and computing chemically reacting turbulent flows. The project is focused on the application of the newly developed Coherent Vortex Simulation (CVS) method to study the mixing in turbulent reacting flows. In the CVS method the conservation equations are solved in a compressed basis obtained by wavelet filtering. Compared to the state of the art in modelling, Large Eddy Simulation (LES) methods which discard the small scales and model its influence on the large scales of the flow, CVS automatically adapts the computational grid during the flow evolution to resolve the regions where strong gradients develop. Even though CVS calculations are performed in a highly compressed basis and, therefore, save computational resources, the results are very consistent with those obtained from DNS calculations, which are model free and resolve all scales. Thus, this new computational method is particularly well suited to study reacting flows where the chemical reactions mostly occur on fine scales and often very locally in space. The aim of this proposal is to develop new multiscale turbulence models and numerical codes based on CVS to accurately simulate turbulent reacting flows in complex geometries at high Reynolds numbers and high Schmidt numbers, as encountered in many applications in chemical engineering and in geophysical flows.

湍流反应流的特征在于它们的大量活动时间和空间尺度。在大多数情况下，小空间尺度的小尺度是脱钩的，而速度却无法实现快速的时间尺度。多尺度表示，例如小波底座，可以避免这种障碍物，因此有望建模和计算化学反应的湍流。该项目的重点是应用新开发的相干涡流模拟（CVS）方法来研究湍流反应流中的混合。在CVS方法中，通过小波滤波获得的压缩基础求解了保护方程。与建模中的最新技术相比，大型涡流模拟（LES）方法丢弃了小尺度并建模其对流量大尺度的影响，CVS会在流动演化过程中自动适应计算网格，以解决强大梯度发展的区域。即使CVS计算是以高度压缩的基础进行的，因此可以节省计算资源，但结果与从DNS计算中获得的结果非常一致，DNS计算是无模型并解析所有量表的结果。因此，这种新的计算方法特别适合研究化学反应主要出现在细尺度上，并且通常在空间中非常局部的反应流。该提案的目的是基于CVS开发新的多尺度湍流模型和数值代码，以准确模拟高雷诺数和高schmidt数量的复杂几何形状中的湍流反应流，如化学工程和地球物理流中的许多应用中所遇到的那样。