Secondly, the dispersion equation of longitudinal wave is derived based on the transmission model that longitudinal waves propagate along the periodic structure such as the drill strings or oil pipe.

• 其次，建立了理想钻杆和油管这种宏观周期性结构中沿管轴方向传播的纵波传播模型，推导出了纵波的频率方程(色散方程)。