Digital imaging techniques for measurement of velocities and sediment size, concentration and entrainment rate in open channel flow

In this three part study, digital imaging methods were used to measure the instantaneous flow field and sediment entrainment in open channel flow. In the first portion an Automated Sediment Erosion Testing System (ASETS) was developed and applied to determine profiles of the critical shear stress and erosion rate for undisturbed field sediment cores. In the second part suspended sediment size and concentration in a tank of water were determined from digital images, illuminated by a uniform, broadband back-lighted source. In the third portion sequential PIV and back-lighted image were used to measure instantaneous velocities and suspended sediment sizes, concentration and movement in the wall, log, and outer regions of open channel flow.