Stresses and Drag in Turbulent Bed Load From Refractive Index-Matched Experiments
Journal
Geophysical Research Letters
Journal Volume
45
Journal Issue
14
Pages
7000-7009
Date Issued
2018
Author(s)
Abstract
Abstract We report steady open‐channel flow experiments that resolve the internal dynamics of turbulent bed load layers at subgrain diameter resolution. Optical access is gained by using materials of matched refractive index, and a laser light sheet is scanned across the medium to capture both the solid and liquid motions over a 3‐D volume. The imaging measurements yield vertical profiles of granular concentration, solid and liquid mean velocity, and velocity fluctuation statistics including the granular temperature and the Reynolds stress. This makes it possible to determine all principal contributions to the momentum balance of each phase. In particular, experimental profiles are obtained for the stresses and interphase drag force. They are used to test constitutive relationships derived from kinetic theory, turbulence theory, and fluidization cell experiments.
Type
journal article