Acoustic scattering by a three-dimensional elastic object near a rough surface

Area of Science:

• Acoustic scattering
• Wave propagation
• Geophysics

Background:

• Accurate modeling of acoustic fields scattered by submerged elastic objects is crucial for detection and identification.
• Environmental factors like surface roughness and object proximity significantly influence scattering patterns.
• Existing models often simplify interfaces as planar, neglecting real-world complexities.

Purpose of the Study:

• To formulate the ensemble-averaged scattered field by elastic objects near randomly rough penetrable surfaces.
• To investigate the impact of surface roughness on acoustic backscattering from buried objects.
• To explore strategies for enhancing the detection and identification of submerged targets.

Main Methods:

• Combined perturbative solutions for rough surface propagation with transition (T-) matrix solutions for object scattering.
• Assumed fluid media bounding the rough surface.
• Applied the formulation to a spherical steel shell in a rough sediment environment.

Main Results:

• Ensemble-averaged incoherent intensity backscattered by buried objects is enhanced at high frequencies due to surface roughness.
• This enhancement offers improved detection over models assuming planar surfaces.
• However, interface-scattered incoherent intensity can hinder detection.

Conclusions:

• Surface roughness significantly impacts acoustic scattering from buried elastic objects, particularly at high frequencies.
• The coherent field component shows minor deviations from planar interface predictions but offers strategies for long-range detection.
• Understanding roughness effects is key to improving sonar-based detection and identification systems.