Acoustic backscatter inversion for suspended sediment concentration and size: A new approach using statistical inverse theory

Wilson, Gregory; Hay, Alexander

doi:10.1016/j.csr.2015.07.005

Cited by 23 publications

(19 citation statements)

References 35 publications

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“…11 correspond with modified f and expressions, as calculated from the Betteridge, Thorne and Cooke [40] model that have also been corrected for density in the given relationships (f/√ and / ). These are similar to functions reported by Moate and Thorne [37], as used by Wilson and Hay [51], who also investigated particle types with a range of densities, although there are some key differences. Moate and Thorne [37] normalised f and by the grain density and not the density ratio (as has been done here) and therefore did not strictly retain non-dimensionality.…”

Section: Density-normalised Form Function and Total Normalised Scattesupporting

confidence: 86%

Measurement and density normalisation of acoustic attenuation and backscattering constants of arbitrary suspensions within the Rayleigh scattering regime

et al. 2019

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The scattering and attenuation of megahertz frequency acoustic backscatter in liquid suspensions, is examined for a range of fine organic and inorganic particles in the Rayleigh regime, 10 -4 < ka < 10 0 (where k is the wavenumber and a the particle radius) which are widely industrially relevant, but with limited existing data. In particular, colloidal latex, mineral titania and barytes sediments, as well as larger glass powders were investigated. A manipulation of the backscatter voltage equation was used to directly measure the sediment attenuation constants, . Decoupling of the combined backscattering-transducer constant, allowing explicit measurement of the backscattering constant, ks, was achieved through calibration of the transducer constant, kt. Additionally, the methodology was streamlined via averaging between a number of intermediate concentrations to reduce data variability. This approach enabled the form function, f, and the corresponding total normalized scattering cross-sections, , to be determined for all species. While f and are available in the literature for large glass and sand, this methodology allowed extension for the colloidal organic and inorganic particles. Specific gravity normalisation of f collapsed all data onto a single distribution, with the exception of titania, due to scattering complexities associated withagglomeration. There was some additional variation in , with measured values of the fine particles up to of magnitude greater than the density-normalised prediction at low ka . Mechanisms accounting for these variations from theory are however analysed, and include viscous attenuation effects, the polydispersity of the particle type and increasing influence of the solvent attenuation.Additionally, thermoacoustic losses appeared to dominate the attenuation behaviour of the organic latex particles. This study demonstrates that particles close to the colloidal regime can be measured successfully with acoustic backscatter, and highlights the great potential of this technique to be applied for in situ or online monitoring purposes in such systems.

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Section: Density-normalised Form Function and Total Normalised Scattesupporting

confidence: 86%

Measurement and density normalisation of acoustic attenuation and backscattering constants of arbitrary suspensions within the Rayleigh scattering regime

et al. 2019

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“…These studies' results confirmed that particle size and concentration can be estimated relatively non-intrusively and with high spatial and temporal resolution using ABS (Thorne and Thorne et al, 1998). However ABS is an indirect method and an inversion algorithm is required to convert the backscattered signal to a sediment concentration (Wilson and Hay, 2015;Clay and Medwin, 1997).…”

Section: Introductionsupporting

confidence: 54%

Analyses of Turbidity and Acoustic Backscatter Signal With Artificial Neural Network for Estimation of Suspended Sediment Concentration

Meral¹

2018

Appl. Ecol. Env. Res.

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Abstract. The commonly used sampling method is restrictive for the spatial and temporal measurement of suspended sediment and requires intensive labor. These limitations and technological advances have led to methods based on sound or light scattering in water. In this study, the turbidity and acoustic backscattering signal (ABS) values were used with the aim of improving these methods with different artificial neural network (ANN) models; Multilayer Perceptron (MLP), Radial Basis Neural networks (RBNN) and General Regression Neural Network (GRNN). Measurements were taken in a vertical sediment tower for two different sediment sizes (< 50 µm and 50-100 µm) and concentrations (0.0-6.0 g L -1 ). In the results of the regression analyses, turbidity values had strong relationships with sediment concentration for both sediment size groups (R 2 = 0.937 and 0.967). Although the ABS values had a reasonable R 2 value (0.873) for the 50-100 µm group, the < 50 µm group did not produce a significant R 2 value with regression analyses. The remarkable differences were not observed among MLP, RBNN and GRNN model for this sediment size group, and the reasonable R 2 and RMSE results were not produced with any ANN model that had a single ABS input for the < 50 µm sediment group. On the other hand, for the other sediment group (50-100 µm), ABS values were used as a single input, and the highest R 2 (0.917) value was obtained with MLP model and it was improved with the turbidity input (up to R 2 = 0.999). The results show that the ANN model could be considered as an alternative method because it was applied successfully to estimate suspended sediment concentration using with turbidity and ABS under different particle size conditions.

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“…Limitation of ADCP in observing different grain sizes of suspended sediment has been described previously by researcher (e.g., [5]). The ADCP instrument was unable to distinguish between large particle sizes and small particle sizes that accumulate in particular volume in this research, so the measurement using ADCP will be slightly lower in estimating the suspended sediment concentration [26]. However, in other studies different results were found, that is, overestimation in the estuary because of relatively large events on net suspended sediment flux [27].…”

Section: Comparison Between Adcp-based Ssc and Laboratorybased Sscmentioning

confidence: 53%

Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

Dwinovantyo

Manik

Prartono

et al. 2017

Advances in Acoustics and Vibration

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The application of Acoustic Doppler Current Profiler (ADCP) can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC) from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient ( ) 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.

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Acoustic backscatter inversion for suspended sediment concentration and size: A new approach using statistical inverse theory

Cited by 23 publications

References 35 publications

Measurement and density normalisation of acoustic attenuation and backscattering constants of arbitrary suspensions within the Rayleigh scattering regime

Measurement and density normalisation of acoustic attenuation and backscattering constants of arbitrary suspensions within the Rayleigh scattering regime

Analyses of Turbidity and Acoustic Backscatter Signal With Artificial Neural Network for Estimation of Suspended Sediment Concentration

Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

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