Estimation of Sediment Incipient Velocity Using B-Mode Ultrasound Imaging Technique

Sediment incipient velocity(SIV) is a vital parameter for sediment research and river dynamics. This paper describes a novel method of estimating SIV based on the known flow velocity in the movable-bed model experiment. In this method, we use B-mode ultrasound imaging technique to get video images of moving particles and topography under water. By statistical analysis of video images, the relationship between the average number of imaging particles and flow velocity is obtained. The relationship between the change rate of average number and flow velocity is analyzed in sediment incipient process. These relationships are used to estimate the SIV. Lastly, the changed topography verifies the estimated velocity. The results show there is a sudden change in these relationships which can be used to estimate the SIV with high resolution by using a B-mode ultrasound device. The estimated SIV of plastic sands(particle size is about 0.25 mm) is 3.64 cm · s–1 and the estimated SIV of natural sands(particle size is about 0.25 mm) is 5.47 cm · s–1 in the same condition.