Simulation of wind-generated surface waves and effects of bubbles on scattering, transmission, and attenuation of low frequency sound at the sea surface

Abstract

Sea surface virtual acoustic simulator lab (SSVASL) is a software based on a newly presented reformed Helmholtz-Kirchhoff-Fresnel method developed in FORTRAN programming language. Based on the resonance dispersion model (RDM), bubbles deformation at frequency range below 200 Hz can cause different physical features such as dynamic density and resonance dependence of phase velocity in bubbly water medium. Therefore, the initial Helmholtz-Kirchhoff-Fresnel (HKF) method which only considers the surface roughness effects is optimized as reformed HKF to entail the influence of subsurface bubble population on the arrival of sound to the sea surface. Considering an acoustical system in which scattering, transmission, and attenuation phenomena occur, effects of sea surface on the emitted sound are simulated by SSVASL. The SSVASL code, by considering the RDM model and void fraction of bubbly medium in frequency range below 1000 Hz and wind-generated surface waves, is capable of providing surface scattering strengths, transmission change, and damping coefficients of rough bubbly air–water interface for a localized point source. For verification purposes, experimental results of critical sea tests, FLIPEX software, and prominent Tolstoy’s approach are considered in sound scattering, transmission, and attenuation phenomena at the sea surface, respectively. The obtained procedure and results can be very helpful in many acoustics-related studies in the ocean environment including acoustic Doppler current profiler, sonar performance, marine life, and oceanography among others.