Bistatic scattering from an anisotropic rough surface in water tank
Résumé
The objective of this work was to study the scattering strength depending on the receiver and sound source positions compared to an anisotropic surface. Roughness scattering by an anisotropic rough surface was studied under controlled laboratory conditions at a frequency of 500kHz. Two kinds of anisotropic rough surfaces were used, both with a height of 3mm, but one with a wavelength of 2.5cm the other of 5cm. The measurements have shown strong scattering behaviors depending on the direction of the propagation plane on the rough surface. In the smoother direction, scattering strength was observed around the specular direction, whereas for the rougher direction, the scattering strength showed maxima and minima at specific scattered angles. These angular positions were closely related to the shape of the surface as well as to the relationship between dimensions and the acoustic frequency. The experimental results were compared with simulations performed using the small slope approximation of first order and an appropriate roughness correlation function. This comparison showed good agreement between experimental data and simulations in terms of roughness scattering behavior.