Abstract A general class of acoustic impedance conditions is considered where a linear dependence is assumed between the fluid velocity and the surface traction. In addition to the classical impedance relating pressure and normal velocity, this generalised definition of the impedance includes effects such as the friction along the surface as well as coupling between the normal velocity and the tangential force on the fluid. After providing a generalised definition based on impedance and admittance matrices, various fundamental principles are considered to ensure the impedance is physically admissible. These principles include the reality, causality, stability and passivity of the surface. To illustrate the influence of the additional parameters introduced by the generalised impedance, a number of results are presented for the reflection of a plane wave on a lined surface, with or without a mean flow.

中文翻译：

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粘性流体的广义声阻抗

摘要 考虑了一类通用的声阻抗条件，其中假定流体速度和表面牵引力之间存在线性关系。除了与压力和法向速度相关的经典阻抗之外，阻抗的这种广义定义还包括诸如沿表面的摩擦以及法向速度与流体上的切向力之间的耦合等效应。在提供基于阻抗和导纳矩阵的广义定义之后，考虑了各种基本原则以确保阻抗在物理上是可接受的。这些原则包括表面的真实性、因果性、稳定性和被动性。为了说明广义阻抗引入的附加参数的影响，