Turbulent characteristics inside ingoing multi-bend rivers

摘要

Understanding flow structure inside meandering rivers with different physical properties can be very important to river bank protection, design the artificial canals and also numerical simulations. The effect of different curvatures and also sequential bends on turbulent characteristics are studied in detail for ingoing river meanders. Two physical models of meandering river present strongly curved and mild bends were designed. The models were installed inside a 15 m length flume, separately. Each river meander model consists of three sequential bends and experimental tests were performed inside the second bend. The three-dimensional velocity of flow in five cross-sections of each model was measured in 720 nodal points using Micro-acoustic Doppler velocity meter (ADV). At each nodal point, 6000 velocity data for each direction were stored in a computer. Reynolds shear stress, turbulent kinetic energy and turbulent intensity were analyzed. On the basis of these experiments, the effect of centrifugal force of previous and next bends on flow structure of second bend in the strongly curved multi-bend is stronger than mild's. The present result can also be useful to predict the bed topography.