Abstract The vibro-acoustic behavior of a semi-submerged finite cylindrical shell is studied theoretically and experimentally. An analytical form of the vibro-acoustic coupling equation is developed using the wavenumber transformation and separation of variables for the sound pressure and the mode expansion for the shell's motion. The far-field radiation sound pressure is derived by utilizing the stationary-phase approximation. The radial velocity, radiated sound power, and sound pressure directivities (including the circumferential and axial directivities) from analytical models are compared with numerical and experimental results to verify the method. The assumption that the shell is terminated by semi-infinite rigid baffles is the main reason for the deviations between the analytical and experimental results. Below the ring frequency, acoustic radiation from a semi-submerged finite cylindrical shell occurs primarily because the air–liquid demarcation points on the shell surface act as radiation sources. Therefore, the circumferential and axial directivity patterns of a semi-submerged finite cylindrical shell can be approximated as a superposition of two in-phase dipoles formed by the air–liquid demarcation points and as a superposition of two in-phase dipole line sources, respectively. Simple formulas are derived to predict the circumferential and axial directivity patterns. This is a new and simplified approach for predicting the directivity patterns of a semi-submerged finite cylindrical shell. The vibro-acoustic behavior of a semi-submerged finite cylindrical shell differs from that of a submerged shell, especially the circumferential directivity pattern due to the reflection from the free surface.

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半浸没式有限圆柱壳振动声学特性的分析与实验研究

摘要 对半浸没式有限圆柱壳的振动声学行为进行了理论和实验研究。振动声耦合方程的解析形式是使用声压变量的波数变换和分离以及壳运动的模式展开来开发的。远场辐射声压是通过使用固定相位近似推导出来的。将解析模型的径向速度、辐射声功率和声压方向性（包括周向和轴向方向性）与数值和实验结果进行比较，以验证该方法。外壳由半无限刚性挡板终止的假设是分析和实验结果之间存在偏差的主要原因。低于振铃频率，来自半浸没式有限圆柱壳的声辐射主要是因为壳表面上的气液分界点充当辐射源。因此，半浸没式有限圆柱壳的周向和轴向方向图可以分别近似为由气液分界点形成的两个同相偶极子的叠加和两个同相偶极线源的叠加。 . 推导出简单的公式来预测周向和轴向方向性模式。这是一种新的简化方法，用于预测半浸没式有限圆柱壳的方向性模式。半浸入式有限圆柱壳的振动声学行为不同于浸入式壳的振动声学行为，