Articles scientifiques
Alex E Hay (1983)
On the Remote Acoustic Detection of Suspended Sediment at Long Wavelengths
Journal of Geophysical Research, 88(C12):7525–7542.
Experimental results are presented which indicate a linear relation between the time-averaged amplitude of the envelope of the backscattered acoustic pulse at 192 kHz and the square root of suspended sediment concentration in the 10 to 103 mg 1−1 range. Particle sizes ranged from 2 to 140 μm. The measurements were made in a negatively buoyant, mine-tailing discharge plume in a submarine channel at depths of 60 to 90 m in Rupert Inlet, British Columbia. From the theory of acoustic backscatter from a solid elastic sphere in the Rayleigh region it is shown that if the pressure amplitude of the backscattered wave is Rayleigh distributed, then such a linear relation is to be expected. Expressions for the optimum acoustic frequency for the detection of dilute suspensions at a given range and for the minimum detectable concentration are obtained assuming a thermal noise background. The possibility that bubbles contribute to the backscatter is considered and found to be unlikely on the basis of probable bubble lifetimes
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