Measuring Low Sediment Concentrations and Vertical Distributions Based on B-Mode Ultrasound Imaging

Using B-mode ultrasound diagnostic apparatus in the silt carrying flow, a new method of measuring low sediment concentrations and their vertical distributions is proposed in the model experimentation. Through the research of imaging signals of suspended sediment obtained directly by B-mode ultrasound in the water, the features of images such as imaging area concentration and grayscale area concentration of sand imaging spots are gotten, and a good relationship existed between the features and the actual sediment concentration is proved within certain realms, and then the relationship is used to measure unknown sediment concentrations after a rating curve is established by calibration test. The results demonstrate that the method is suitable for the measurement of sediment when volume concentration below 4.0 parts per thousand or about 10 kg/m(3) by weight. With the advantages of direct observation, high sensitivity, good real-time and no disturbance, this method is especially suitable for the measurements of low sediment concentrations and the analysis of sediment dynamic migration in the river and port engineering model test.