Numerical simulation of flow characteristics in elongated annular flume

A complex annular flume, consisting of 2 straight flumes and 2 semicircular flumes, is built for invastigation of the hydrodynamic characteristics of water flow driven by a moving lid on the water surface. The CFD software developed by Fluent Inc. is used for simulation of 3D hydrodynamic characteristics of water flow in the flume, and the simulated result is in good agreement with that observed by ADV. The research shows that in the curved section of the flume, there exists a strong secondary flow, and the velocity tends to increase significantly in the radial direction from the inside to the outside, and that in the straight section near the outlet of the curved section, the velocity distribution has the same characteristics as that in the curved section due to the effect of convection, but, with the increase of flow distance, the velocity in the transversal direction tends to be uniform. Owing to the simple flow structure in the straight section near the outlet of the curved section, the elongated flume can be effectively used for investigation of the interaction between sediment motion and water hydrodynamics as compared with the simple annular flume.