FLOW CHARACTERISTICS AND BED VARIATIONS IN A MEANDERING CHANNEL WITH FLOOD PLAINS

The experimental studies are described for the characteristics of flows over aflat rigid and an equilibrium rigid bed as well as for the bed variations in ameandering channel with flood plains, which are conducted under the conditions ofthree stages; under-bankfull, bankfull and over-bankfull flows. A lot of significantresults are obtained from the investigations. Some of these are summarized asfollows:Velocity distributions of the over-bankfull meandering flow show that the flowin overbank tends to meander and, on the contrary, the meandering of the flow ininbank becomes flatter than that of under-bankfull flow and its phase is shifteddownstream. Three outstanding features are found in the equilibrium bedconfiguration of over-bankfull flow. Those are the phase shift downstream of deepscouring position, the decrease of scouring depth and the expansion of scouringrange. The reasons for these phenomena are also discussed in the present paper.The experimental studies are described for the characteristics of flows over aflat rigid and an equilibrium rigid bed as well as for the bed variations in ameandering channel with flood plains, which are conducted under the conditions ofthree stages; under-bankfull, bankfull and over-bankfull flows. A lot of significantresults are obtained from the investigations. Some of these are summarized asfollows:Velocity distributions of the over-bankfull meandering flow show that the flowin overbank tends to meander and, on the contrary, the meandering of the flow ininbank becomes flatter than that of under-bankfull flow and its phase is shifteddownstream. Three outstanding features are found in the equilibrium bedconfiguration of over-bankfull flow. Those are the phase shift downstream of deepscouring position, the decrease of scouring depth and the expansion of scouringrange. The reasons for these phenomena are also discussed in the present paper