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.

湍流反应流的特点是其大范围的活动时间和空间尺度。在大多数情况下，无法实现小尺度与大空间尺度以及慢尺度与快时间尺度的分离。多尺度表示，如小波基，允许绕过这一障碍，因此，有前途的建模和计算化学反应湍流。本计画主要应用新发展之相干涡模拟法（CVS）来研究紊流反应流中之混合。在CVS方法中，守恒方程在小波滤波得到的压缩基中求解。与最先进的建模方法相比，大涡模拟（LES）方法丢弃小尺度并模拟其对大尺度流动的影响，CVS在流动演变过程中自动调整计算网格以解决强梯度发展的区域。尽管CVS计算是在高度压缩的基础上进行的，因此节省了计算资源，但结果与DNS计算结果非常一致，DNS计算是无模型的，可以解决所有尺度。因此，这种新的计算方法特别适合于研究反应流，其中化学反应大多发生在精细尺度上，并且通常在空间中非常局部。本建议的目的是开发新的多尺度湍流模型和数值代码CVS的基础上，以准确地模拟湍流反应流在复杂的几何形状在高雷诺数和高施密特数，在许多应用中遇到的化学工程和地球物理流。