随机起伏界面声散射的实验与理论研究

进行了二维粗糙海面声波散射特性的水池实验,测量了不同入射角、散射角以及方位角条件下所对应的散射强度。实验通过不同位置风扇对水面的吹拂获得粗糙水面,分别对水平面上互相垂直的两个方向上的水面波高变化进行了测量,利用周期图法估计出这两个方向上的空间功率谱,验证了实验中的粗糙水面是各向同性的。利用改进的空间域处理技术去除了总声波信号中的直达波和其他固定位置散射体的散射信号,获得了粗糙水面的声波散射信号。利用小斜率近似方法计算了二维粗糙海面的声散射特性。实验与模拟计算结果比较,证实了计算二维粗糙海面声波散射特性的小斜率近似方法的有效性与准确性,相互印证了实验与理论。

Experimental and theoretical research on acoustic scattering strength of rough surface

An experiment about acoustic scattering strength of rough sea surface has been conducted at pool. The variation of the scattering strength with different incident angles, scattering angles, and azimuth angles are measured. In the experiment, fans at different positions are used to obtain the rough sea surface. And the rough sea surface＇s spatial power spectrum density is obtained with the method of period gram method. The horizontal spatial power spectrum density is compared with the vertical one, and the result shows that the rough sea surface is isotropic. In order to eliminate the direct signal and the scattering signals from the scatters at other fixed positions in the total rough surface scattering signal, a spatial domain processing method is introduced. Acoustic scattering from the 2-D rough surface by the small slope approximation theory is studied, and the scattering strength of the rough sea surfaces is calculated. The comparison of the results between the experiment and the simulative calculation validates that the small slope approximation theory is effective and correct. And so, the validity of both the experiment and the theory is verified.