Sound Scattering in Aqueous Suspensions of Sand: Comparison of Theory and Experiment
Theoretical estimates of the form factor and the linear attenuation coefficient are compared with the available data for dilute aqueous suspensions of sand. As far as the existing data are concerned, the measured attenuation coefficients are the most useful. The available data on scattered intensities are too few for the comparison with theory to be conclusive. From the comparisons with the attenuation data it appears that a spherical model is a reasonable approximation. Three theoretical models are considered, in which the spherical scatterer is assumed to be either elastic, or completely rigid, or both rigid and immovable. The rigid movable model provides the best fit to the data. The comparatively poor agreement with the results from the elastic model indicates that resonance excitation does not occur, probably because natural sand grains are irregularly shaped and inhomogeneous in composition. The rigid immovable model fits the data the least well, indicating that the inertia of the particles is important. Approximate expressions for the form factor and attenuation coefficient have also been constructed, based on the so-called high-pass model introduced by Johnson (1977). The high-pass model provides a fit to the data which is as good as the rigid movable case.
KeywordsForm Factor Attenuation Coefficient Aqueous Suspension Scattered Intensity Resonance Excitation
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