Fluid-acoustic coupling and wave propagation

该项目的重点是数值模拟的噪声产生和传播内和附近的流场。这是在时域中完成的，以实现与计算流模拟和关于噪声产生机制的物理解释的密切交互。考虑波传播的数值方法是基于有限体积（FV）以及有限元（FE）的方法，旨在捕捉波传播与高分辨率这些计划的一个重要优势是他们的直接扩展到非笛卡尔和非等距网格。但似乎有几个候选人具有更好的波传播特性比标准的有限差分DRP格式。对于流场的耦合，考虑了两种主要方法。对于低马赫数流动，本文从理论和实践两方面研究了一种基于多尺度渐近分析的摄动方法。这些考虑也扩展到低马赫数流动与热传导。验证和与其他扰动方法或类比performined相对于亚音速混合剪切层和射流。对于强可压缩流动，进行了流场求解器与声学求解器的表面耦合。建立了非线性和线性数学模型的无反射耦合，并进行了检验，允许界面处的不连续通量。

This project is focused to the numerical simulation of noise generation and propagation within and in the vicinity of the flow field. This is done in the time domain to enable a close interaction with the computational flow simulation and the physical interpretation with respect to the noise Generation mechanisms. The numerical methods for wave propagation considered are based on the finite-volume (FV) as well as the finite-element (FE) approach and are designed to capture wave propagation with high Resolution An important advantage of these schemes is their straightforward extension to non-Cartesian and non-equidistant grids. But it seems that there are several candidates with better wave propagation properties than the standard finite difference DRPschemes. For the coupling to the flow field two main approaches are considered. For low Mach number flow a perturbation method based on multi-scale asymptotic analysis is investigated from practical and theoretical point of view. These considerations are also extended to low Machnumber flow with heat conduction. Validation and a comparison with other perturbation methods or analogies is perforined with respect to subsonic mixing shear layer and jet flow. For strongly compressible flow a surface coupling of the flow solver with the acoustic solver is perforined. A nonreflecting coupling of the nonlinear and linear mathematical model is established and tested, allowing discontinuous fluxes at the interface.