以简正波解为初始场的抛物方程算法应用于深海声传播预报

在深海中,环境参数不仅在深度上起伏变化,在水平方向上也会因内波、涡旋、锋面、洋流等现象而发生变化。对于深海声传播的预报,仍是一个值得进一步探讨的问题。简正波方法具有物理意义明确、但仅适用于水平方向环境参数不变的波导的特点,而抛物方程方法能够便捷地处理与深度、距离有关的声速、地形等环境,但其解缺乏清晰的物理意义。采用简正波解为抛物方程法的初始场,利用Ram随距离逐步递推的数值方法计算整个海域的声能量,计算存在涡旋等复杂海洋环境下的声传播特点。结果表明,该方法不仅可以计算各种环境条件下的各阶简正波的传播特点以及能量变化,而且便于深入地分析深海环境中各阶简正波的耦合特点与能量变化,计算效率大大提高且具有很高的准确性。可以作为浅海和深海中高、低频传播的通用模型。

Application of a parabolic-equation algorithm with normal solution as the initial field to acoustic propagation modelling in deep sea

The acoustic propagation model Kraken can calculate the normal mode in the range-independent environment and the parabolic model Ram has the ability to compute the sound field in the range-dependent ocean environment. A parabolic equation algorithm with normal solution as the initial field is proposed in this paper. This method uses the normal mode method Kraken to calculate the single or multiple normal modes as the parabolic model''s initial field and calculate the energy distribution and propagation characteristics of arbitrary normal mode in the arbitrary ocean environment, so as to analyze the normal mode coupling. Besides, this method can not only overcome the low frequency limitation of coupling model, but also upgrade the computational efficiency with high accuracy. It can be used as a general model for high or low frequency acoustic propagation in shallow sea or deep sea.