自由边界固体圆柱中导波的频散与发射

The Frequency Spreading and Excitative of the Guided Waves in a Solid Cylinder with Free Boundary

为了研究自由边界波导中的激发与传播机制。文章对自由边界固体圆柱中的导波进行了理论求解，推导出了导波的频散方程和激发幅度公式。在固体圆柱参数取不同值的情况下，数值分析了多阶导波（模式波）的频散与激发特性。数值模拟了在固体圆柱轴上记录到的由一阶导波贡献的时间波形。计算结果表明：沿固体柱存在两类导波，一类导波无截止频率，另一类导波存在截止频率。频散曲线和激发曲线与固体圆柱本身的参数有直接关系。这些理论和分波分析一致。说明所提出的模型可取，数值计算方法与程序可靠。

In order to study the excitation and spreading mechanism, theoretical solution to guide wave in a solid cylinder surrounded by free boundaries was researched In this way, the spreading equation of the guided wave and the formula of the excitative range were reasoned out In the case of possible value of formation parameter, dispersion and excitation feature of the multi-order guide wave (moder wave) was analysed The first order guide wave form recorded on solid cylinder axis is numerically modeled It turned out to be two forms of waves about the solid cylinder, one is the limitless frequency, the other is the limited one It also shows that the spreading and excitative curve lines have close relationship with the parameter Based on this agreement of the theory and analysis, the model put forward is quite acceptable and its calculation and process are reliable