Normal Modes and Modal Reduction in Exterior Acoustics
Normal Modes and Modal Reduction in Exterior Acoustics
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DOI：
10.1142/s2591728518500299
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发表时间：
2018-09
影响因子：
1.9
通讯作者：
Lennart Moheit;S. Marburg
中科院分区：
文献类型：
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作者：
Lennart Moheit;S. Marburg
外声问题的亥姆霍兹方程可以用有限单元法和共轭无限单元法相结合来求解。两者都提供与频率无关的系统矩阵，形成一个离散的线性方程组。齐次系统可以理解为正规模态（NMs）的二次特征值问题。在进行模态叠加时，对唯一相关的NMs的了解仍然提供了与全套模态相比足够精确的声压和声功率解，从而减少了计算工作量。本文讨论了NMs的性质和模态约简准则。
The Helmholtz equation for exterior acoustic problems can be solved by the finite element method in combination with conjugated infinite elements. Both provide frequency-independent system matrices, forming a discrete, linear system of equations. The homogenous system can be understood as a quadratic eigenvalue problem of normal modes (NMs). Knowledge about the only relevant NMs, which — when doing modal superposition — still provide a sufficiently accurate solution for the sound pressure and sound power in comparison to the full set of modes, leads to reduced computational effort. Properties of NMs and criteria of modal reduction are discussed in this work.