Statistical Analysis of Sediment Motions on Dunes

Statistical analyses were done on the movements of bed load particles over alluvial bed forms from data collected in a large laboratory flume at Colorado State University. The bed load particles were tagged by radioactive tracer — Cesium 137. Statistical properties of the random variables and the correlations between these variables are investigated. It is found that within the test range, the mean and variance of longitudinal step length, the mean wavelength and the mean wave height of bed forms, the particle speed, the variance of vertical step length, and the variance of lateral step length all increase with the increase of flow. However, the coefficients of variation for both wave height and wavelength remain approximately the same for all flow conditions tested. The ratio of average wave length to average wave height decreases with the increase of flow.