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.
KeywordsAttenuation Compressibility Cross Correlation Remote Sensing Acoustics
Unable to display preview. Download preview PDF.
- Flammer, G. H., 1962, Ultrasonic Measurement of Suspended Sediment, Geological Survey Bulletin 1141-A, US Government Printing Office, Washington.Google Scholar
- Jansen, R. H. J., 1979, An Ultrasonic Doppler Scatterometer for Measuring Suspended Sand Transport, in “Ultrasonic International 79, Conference Proceedings, Graz, Austria”, IPC Science and Technology Press, Guildford, U.K.Google Scholar
- Reagan, J. A., and Herman, B. M., 1980, “Light Scattering by Irregularly Shaped Particles Versus Spheres: What are some of the Problems presented in Remote Sensing of Atmospheric Aerosols?”, in “Light Scattering by Irregularly Shaped Particles”, D. W. Schuerman, ed., Plenum Press.Google Scholar
- Schaafsma, A. S., and der Kinderen, W. J. G. J., 1985, Ultrasonic Instruments for the Continuous Measurement of Suspended Sand Transport, in “Proc. IAHR Symp. on Measuring Techniques in Hydraulic Research”, Balkema Publ. Rotterdam.Google Scholar
- Sheng, J., 1986, “Sound Scattering and Attenuation in Aqueous Suspensions of Sand: Comparison of Theory and Experiment”, M.Sc. Thesis, Memorial University of Newfoundland.Google Scholar