次声波在平流层波导中传播的数值模拟

A numerical study on infrasound propagation in stratospheric duct

对次声波在大气中传播进行了建模。通过结合保色散关系空间差分格式和Runge-Kutta时间格式的数值方法,建立了次声波传播模型。应用该次声波模型,研究了在耗散的重力分层大气中次声波的平流层导行传播。数值模拟结果表明,当次声波波包在平流层高度上被反射时,反射区域存在焦散现象,在声波的声压下降的同时,声波的能量得到聚焦。通过数值模拟结果与射线计算结果的对比表明,大气中声波传播的轨迹的精确描述需要应用全波解。

The propagation of infrasound in the atmosphere is modeled. By using a finite-difference time-domain method consist of a dispersion relation preserving scheme in space and a Runge-Kutta scheme in time, an infrasound propagation model is developed. The stratospheric ducted propagation of infrasound in a dissipative, gravitational stratified atmosphere is studied by this model. The simulation result shows that the caustic phenomenon occurs in the reflecting region at the height of the stratosphere, the sound pressure of the infrasound decreases while its energy is focused. Compared to the result of ray model, to make a precise prediction of the trajectory, the full wave solution should be employed.