In the previous investigations of the vibroacoustic characteristics of a submerged cylindrical shell in a flow field, the fluid viscosity was usually ignored. In this paper, the effect of fluid viscosity on the characteristics of vibration power flow in an infinite circular cylindrical shell immersed in a viscous acoustic medium is studied. Flügge’s thin shell theory for an isotropic, elastic, and thin cylindrical shell is employed to obtain the motion equations of the structure under circumferential-distributed line force. Together with the wave equations for the viscous flow field as well as continuity conditions at the interface, the vibroacoustic equation of motion in the coupled system is derived. Numerical analysis based on the additional-damping numerical integral method and ten-point Gaussian integral method is conducted to solve the vibroacoustic coupling equation with varying levels of viscosity. Then, the variation of the input power flow against the nondimensional axial wave number in the coupled system with different circumferential mode numbers is discussed in detail. It is found that the influence of fluid viscosity on the vibroacoustic coupled system is mainly concentrated in the low-frequency band, which is shown as the increase of the crest number and amplitude of the input power flow curves.

中文翻译：

---

浸没在粘性流体中的无限圆柱壳的振动功率流

在以前的研究中，在流场中浸没圆柱壳的振动声特性通常忽略了流体粘度。本文研究了流体粘度对浸没在粘性声学介质中的无限圆柱壳中振动功率流特性的影响。Flügge针对各向同性，弹性和薄圆柱壳的薄壳理论被用来获得结构在周向分布线力作用下的运动方程。连同粘性流场的波动方程以及界面处的连续性条件，得出了耦合系统中运动的振动声方程。基于附加阻尼数值积分法和十点高斯积分法进行了数值分析，以求解粘度变化的振动声耦合方程。然后，详细讨论了在具有不同圆周模式数的耦合系统中输入功率流对无量纲轴向波数的变化。发现流体粘度对振动声耦合系统的影响主要集中在低频频带，这表现为输入功率流曲线的波峰数和振幅的增加。