Direct inversion method to measure the concentration profile of suspended particles using backscattered sound

Lee, Tae Hwan; Hanes, Daniel M.

doi:10.1029/94jc03068

Cited by 55 publications

(33 citation statements)

References 9 publications

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“…The significant wave height for the particular example shown here was 0.33 m with a period of 5.6 s and the mean water depth was 1.31 m yielding a relative wave height of 0.25; the waves were non-breaking. The mean concentration profile was determined from the simple method outlined above and from the explicit method of Lee and Hanes [10] and Thorne and Hanes [4; their eqn.21]. The explicit method requires an independent estimate of the sediment concentration at a given elevation, which is obtained from the OBS and it assumes a constant particle diameter with elevation above the bed.…”

Section: Mean Concentration Profilesmentioning

confidence: 99%

Measuring suspended sand transport using a pulse-coherent acoustic Doppler profiler

Aagaard

Greenwood

2009

WIT Transactions on Ecology and the Environment

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A simple method to derive sediment transport rates in the nearshore from PulseCoherent Acoustic Doppler Profilers (PC-ADP) is described. Measured sediment concentration profiles are compared with theoretically estimated concentration profiles and exhibit good agreement. Cross-shore and longshore sediment transport rates obtained during 5-6 week long deployments on the lower shoreface in 6-8 m water depth are compared with predictions from an energetics transport model. The two estimates agree to within 20% in the longshore direction while the cumulated cross-shore wave-dominated transport component is trending significantly less offshore for the measurements than for the model predictions. The measurements indicate that significant onshore sediment transport from the lower to the upper shoreface only occurs when waves are close to breaking.

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Section: Mean Concentration Profilesmentioning

confidence: 99%

Measuring suspended sand transport using a pulse-coherent acoustic Doppler profiler

Aagaard

Greenwood

2009

WIT Transactions on Ecology and the Environment

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“…A number of concentration inversion methods exist (Hanes, 2012;Hanes et al, 1988;Lee and Hanes, 1995;Thorne and Hardcastle, 1997;Thosteson and Hanes, 1998) many of which were reviewed in detail by Thorne and Hanes (2002) and Thorne et al (2011). The issue of numerical instability is an important and well known one in both implicit and explicit inversion methods, as it can cause computed particle concentrations to deviate very significantly from the true values to an extent that increases with distance from the transducer(s).…”

Section: Introductionmentioning

confidence: 99%

Measurement of particle concentration in horizontal, multiphase pipe flow using acoustic methods: Limiting concentration and the effect of attenuation

Rice¹,

Fairweather²,

Peakall

et al. 2015

Chemical Engineering Science

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Measurement of particle concentration in horizontal, multiphase pipe flow using acoustic methods: limiting concentration and the effect of attenuation AbstractAn acoustic dual-frequency concentration inversion method, in which the backscattered acoustic signal received by transducers operating in the megahertz range is used to determine the concentration profile in suspensions of solid particles in a carrier fluid and which was originally developed for environmental applications, is applied to arbitrary suspensions of general engineering interest. Two spherical glass and two non-spherical plastic particle types with a range of size distributions and densities are used. Particle concentration profiles in horizontal turbulent pipe flow at Reynolds numbers of 25 000 and 50 000 -below and above the critical deposition velocity, respectively -and nominal concentrations of 0.5, 1 and 3 % by volume are presented for the four particle species, using measured backscattering and attenuation coefficients. In particular, the effects of particle size, density and flow rate on the transport and settling behaviour of suspensions are elucidated. The results demonstrate the potential of this method for measuring the degree of segregation in real suspensions and slurries across a range of challenging application areas, such as the nuclear and minerals processing industries. The limitations of the method are explored in detail through an analysis of the acoustic penetration depth and the application-specific maximum measurable concentration, both of which can be used to determine the most appropriate acoustic frequencies and measurement Highlights Marine model for measuring suspended solid fraction adapted for general use. Glass and plastic particles tested at several fractions in horizontal pipe flow.  Clear differences observed between species and settling and non-settling flows. Limiting concentration and penetration depth derived to inform future experiments. Method has potential for use in several engineering applications.

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“…Acoustic instruments for measuring the SSC such as the Acoustic Backscatter System (ABS) have enabled the measurement of nearly instantaneous concentration profiles [Lee and Hanes, 1995;Osborne and Vincent, 1996;Thosteson and Hanes, 1998]. The Multiple Transducer Array (MTA) has enabled the measurement of bedforms in one dimension [Jette and Hanes, 1997;Hanes et al, 2001].…”

Section: Introductionmentioning

confidence: 99%

Suspended sediment and hydrodynamics above mildly sloped long wave ripples

Chang

2004

J. Geophys. Res.

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[1] We investigate the spatial and temporal distribution of suspended sediment and the associated hydrodynamics over mildly sloped long wave ripples on the inner shelf. These bedforms had wavelengths of approximately 1 m and heights of approximately 5 cm, in a mean water depth of 4 m. The vertical and temporal structures of the suspended sediment concentration (SSC) are consistent with the entrainment of sediment on the offshore flank of the ripple, and rapid vertical mixing at the time of flow reversal, followed by advection onshore by the onshore fluid motion. This work confirms that the mechanism for sediment suspension above low-amplitude, long wave ripples is similar to the vortex formation process expected over steeper vortex ripples. Numerical simulations of the flow using the Dune2d model indicate that a separated rotational flow structure is generated at the flank of the ripple on the seaward side of the ripple crest, near the time of flow reversal. The simulations indicate that only one vortex is formed during each wave period, in agreement with the field observations. This asymmetry is due mainly to the presence of an offshore mean near-bed current of approximately 6 to 8 cm/s. The SSC is calculated by the model and compared to the field observations. A hydraulic bed roughness of 10 to 15 median grain diameters (d 50 ) was used in order to match the model prediction to the observed SSC approximately 1 cm above the seabed (cab). However, the modeled SSC and turbulent kinetic energy were significantly lower than the field observations at elevations exceeding approximately 2 cab.

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Direct inversion method to measure the concentration profile of suspended particles using backscattered sound

Cited by 55 publications

References 9 publications

Measuring suspended sand transport using a pulse-coherent acoustic Doppler profiler

Measuring suspended sand transport using a pulse-coherent acoustic Doppler profiler

Measurement of particle concentration in horizontal, multiphase pipe flow using acoustic methods: Limiting concentration and the effect of attenuation

Suspended sediment and hydrodynamics above mildly sloped long wave ripples

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