2012/08/24 by Glauber T. Silva, Silva, Glauber T., Anderson Bandeira +1
Earth and Planetary Sciences · Engineering · Medicine · #Classical Physics (physics.class-ph) #FOS: Physical sciences #Seismic Imaging and Inversion Techniques #Seismic Waves and Analysis #Ultrasonics and Acoustic Wave Propagation #Ultrasound Imaging and Elastography #Underwater Acoustics Research
paper · pdf · doi:10.48550/arxiv.1208.5065
openalex publication_date 2012/08/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper, the partial-wave expansion method is applied to describe the\ndifference-frequency pressure generated in a nonlinear scattering of two\nacoustic waves with an arbitrary wavefront by means of a rigid sphere.\nParticularly, the difference-frequency generation is analyzed in the nonlinear\nscattering with a spherical scatterer involving two intersecting plane waves in\nthe following configurations: collinear, crossing at right angles, and\ncounter-propagating. For the sake simplicity, the plane waves are assumed to be\nspatially located in a spherical region which diameter is smaller than the\ndifference-frequency wavelength. Such arrangements can be experimentally\naccomplished in vibro-acoustography and nonlinear acoustic tomography\ntechniques. It turns out to be that when the sphere radius is of the order of\nthe primary wavelengths, and the downshift ratio (i.e. the ratio between the\nfundamental frequency and the difference-frequency) is larger than five,\ndifference-frequency generation is mostly due to a nonlinear interaction\nbetween the primary scattered waves. The exception to this is the collinear\nscattering for which the nonlinear interaction of the primary incident waves is\nalso relevant. In addition, the difference-frequency scattered pressure in all\nscattering configurations decays as r-1 \ln r and 1/r, whereas r is\nthe radial distance from the scatterer to the observation point.\n