基于等效密度流体模型的地声参数分析

目前的地声参数反演多采用液态海底模型，但是实际海底为多孔弹性海底。该文在等效密度流体模型基础上，通过计算液态海底和多孔弹性海底的反射系数及传播损失，给出了等效密度流体模型和液态海底模型的等效性分析。数值仿真结果表明在低频情况下，多孔弹性海底给出的快纵波声速与等效密度流体模型给出的声速以及等效密度流体的实部与真实的海底密度基本一致。将等效密度流体模型近似看作液态海底模型进行反射系数和传播损失计算，在小掠射角和远距离时，计算结果表明与多孔弹性海底计算结果具有较好一致性，从而以此为依据确定海底为液态，进行地声参数反演。

Geoacoustic parameters analysis based on effective density fluid model

At present, the inversion of geoacoustic parameters mostly adopts liquid seabed model, but the actual seabed is porous elastic seabed. Based on the effective density fluid model, the equivalence between the effective density fluid model (EDFM) and the liquid seabed model is given by calculating the reflection coefficient and propagation loss of the liquid seabed and the porous elastic seabed. The numerical simulation results show that in the case of low frequency, the fast sound velocity given by the porous elastic seabed is basically consistent with the sound velocity given by the EDFM and the real part of the effective fluid density is basically consistent with the real seabed density. The EDFM is as a fluid modal through calculation of reflection and transmission loss, the results show consistent with porous elastic seabed beyond small grazing angel and far range. Therefore, the seabed can be determined as liquid, and the inversion of geoacoustic parameters can be carried out on this basis.