EFFECTS DUE TO THE SHAPE OF SUSPENDED SEDIMENT PARTICLES IN RUNNING WATER ON ULTRASONIC ATTENUATION SPECTRA

Abstract

Recently, instruments based on ultrasonic attenuation spectroscopy have been developed to measure the concentration and the particle size distribution of suspended sediments in running water. In this paper, we investigated each ultrasonic attenuation spectra for suspensions of sediment particles with irregular shapes and of spherical glass beads, by using an ultrasonic pulse with broad bandwidth. The measured attenuation spectra cover a wide frequency band of 5-8MHz. The experimental results demonstrated that the spectra could be brought into close agreement with the rigid movable sphere model using two equivalent sphere size parameters. The findings indicate that a methodology using equivalent spherical scatterer model is applicable to measurements of the concentration and the particle size distribution of suspended sediments in running water.