B-scan ultrasound imaging measurement of suspended sediment concentration and its vertical distribution

Abstract

In this paper, a novel approach based on B-scan ultrasound imaging is presented to measure suspended sediment concentration (SSC) and its vertical distribution. The relationship between ultrasonic imaging signals and SSCs has been described by specially designed experiments on both natural and plastic sand. Three parameters for imaging measurement are introduced to characterise their relationships: imaging concentration (IC), greyscale concentration (GC) and energy concentration (EC). It is confirmed that these parameter values increase with the sand added in the case of low SSC. Compared with the IC and EC, GC is more suitable for expressing their relationships, which can be used to measure the unknown SSC. The possible influences of particle size, material quality and flow velocity on the relationships are also briefly discussed. Characterised by direct observation, high sensitivity and real-time processing performance, this method has proved suitable for the measurement of SSC below 5.0‰ by volume or approx. 10 kg m−3 by weight, especially for the measurement of vertical sedimentary distribution in the movable-bed model experiment.