The actual impedance of non-reflecting boundary conditions : implications for the computation of resonators
The actual impedance of non-reflecting boundary conditions : implications for the computation of resonators
复制标题
非反射边界条件的实际阻抗：对谐振器计算的影响
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
T. Poinsot
中科院分区：
文献类型：
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作者：
L. Selle;F. Nicoud;T. Poinsot
无反射边界条件是许多可压缩流动计算中的基本要素：这种模拟对边界处的声波处理非常敏感。无反射条件允许声波通过边界传播，零或小水平的反射进入域。然而，必须避免完全无反射条件，因为它们可能导致平均流的不适定问题。已经提出了各种方法来构造边界条件，这些边界条件可以充分地不反射声场，同时仍然使平均流问题很好地提出。本文分析了一种广泛使用的无反射出口技术（Rudy和Strikwerda，Poinsot和Lele）。结果表明，这些作者引入的修正可以导致大的反射能级和非物理共振行为。提出了一个简单的比例来评估松弛系数在这些方法中使用的无反射出口。建议的缩放测试简单的情况下（管道）的理论和数值。
Non-reflecting boundary conditions are essential elements in the computation of many compressible flows: such simulations are very sensitive to the treatment of acoustic waves at boundaries. Non-reflecting conditions allow acoustic waves to propagate through boundaries with zero or small levels of reflection into the domain. However, perfectly non-reflecting conditions must be avoided because they can lead to ill-posed problems for the mean flow. Various methods have been proposed to construct boundary conditions which can be sufficiently non-reflecting for the acoustic field while still making the mean-flow problem well posed. This paper analyses a widely-used technique for non-reflecting outlets (Rudy and Strikwerda, Poinsot and Lele). It shows that the correction introduced by these authors can lead to large reflection levels and non-physical resonant behaviors. A simple scaling is proposed to evaluate the relaxation coefficient used in theses methods for a non-reflecting outlet. The proposed scaling is tested for simple cases (ducts) both theoretically and numerically.