Numerical fluid-structure coupling schemes for high-frequency surface motion

高频表面运动的数值流固耦合方案

• 批准号: 202199312
• 负责人: Professor Dr. Wolfgang Dahmen
• 金额: --
• 依托单位: Institut für Geometrie und Praktische Mathematik (IGPM)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/202199312?language=en
• 关键词: Numerical; fluid; structure; coupling; schemes

The central objective of this project is the numerical simulation of effects on the macroscale that are caused by surface structures (riblets) and/or surface actuation by transversal waves in the spanwise direction on a compressible turbulent flow to predict the local skin friction distribution. Since for the flow regime of interest neither the surface structures nor the actuation frequency can be resolved directly by a discretization of the total computational domain we wish to develop upscaling methods based on homogenization or multiscale modelling. These methods are to be used to transfer those riblet structures and actuation parameters that indeed reduce friction drag into boundary formulations that make macroscopic analyses possible. A central contribution during the first funding period was the development of an appropriate framework for a perturbation analysis that, in contrast to the known methods applies to the relevant geometric and turbulent length scales. A pivotal role is played by the identification of suitable cell problems on the microscale whose solution is used to formulate new effective boundary conditions on the macroscale. While these concepts are formulated in the most transparent way for laminar flows they carry over to turbulent regimes when using appropriate turbulence models which can always be interpreted as regularized Navier Stokes equations. In view of the envisaged relevant geometric and turbulent length scales we believe that, beyond low parameter turbulence models, projection models such as the Variational Multiscale Method are ultimately best suited to correctly capture the interaction of flow and geometric structure/actuation. In the first funding period, the focus was on the development of an upscaling strategy for steady state problems. In addition to the further development of the concepts for turbulent regimes their extension to unsteady problems is the central goal in the second funding period.

该项目的中心目标是对宏观尺度上的影响进行数值模拟，这些影响是由表面结构（肋）和/或表面驱动引起的，这些表面结构和/或表面驱动是由可压缩湍流的展向横波引起的，以预测局部表面摩擦力分布。由于感兴趣的流态的表面结构，也不是驱动频率可以直接解决的总计算域的离散化，我们希望开发基于均匀化或多尺度建模的尺度放大方法。这些方法是用来转移这些脊结构和驱动参数，确实减少摩擦阻力的边界公式，使宏观分析成为可能。第一个供资期间的一个核心贡献是为扰动分析制定了一个适当的框架，与适用于相关几何和湍流长度尺度的已知方法不同。一个关键的作用是通过识别合适的细胞问题的解决方案是用来制定新的有效的边界条件的宏观尺度上的微观尺度。虽然这些概念是以最透明的方式为层流制定的，但当使用适当的湍流模型时，它们会转移到湍流状态，这些湍流模型总是可以解释为正则化的Navier Stokes方程。考虑到所设想的相关几何和湍流长度尺度，我们认为，除了低参数湍流模型之外，投影模型（如变分多尺度方法）最终最适合于正确捕获流动和几何结构/致动的相互作用。在第一个供资期，重点是制定一项针对稳态问题的升级战略。除了进一步发展紊流状态的概念外，将其扩展到非定常问题是第二个供资期的中心目标。