The paper discusses new results of our experimental- and mathematical modeling of sediment-laden open-channel flows in the upper plane bed regime associated with intense transport of sediment. Our recent studies showed that bed-load transport and bed friction are interrelated and classical formulae for bed friction (Nikuradse formula) and bed-load transport (Meyer-Peter and Muller formula) need to be modified to account for the intense transport of sediment.
The new results of our laboratory experiments in a tilting flume are presented and analyzed for different sediment fractions. The analysis is focused on the effect of solids density and size on the solid-liquid flow characteristics as the solids flow rate, flow depth, and bed slope for certain flow rate of water in a channel of given geometry. The experimental results are compared with outputs of our mathematical model simulating the observed phenomena. The simple 1-D model combines hydrodynamic- and sediment-transport equations and enables to use different transport- and friction formulae to predict the solids transport, flow depth and bed slope under the condition of (pseudo-) uniform flow of solid-water mixture in the open channel.