Flow Characteristics in a Rotating Circular Flume

Abstract

Increased construction activity and associated receiving water concerns in the Greater Toronto Area has prompted this study to advance our knowledge on cohesive sediment transport processes in rivers and lake environments. Flow characteristics in a rotating circular flume at the National Water Research Institute (NWRI), Burlington, Ontario were studied using a computational fluid dynamics (CFD) model. The objective of this study was to use a CFD model to predict the complex 3D turbulent flow characteristics, including the tangential flow velocity distribution, turbulent secondary flow circulation patterns, and the bed shear stress distributions. The numerical model was calibrated using experimental data collected using a Laser Doppler Anemometer for velocity profiles and measurements obtained by a Preston tube for bed shear stress distributions. Tangential velocity profiles and bed shear velocity distributions across the rotating circular flume were used to evaluate the accuracy of the model predictions. When compared with experimental smooth bed shear stress data, the model performed reasonably well for the range of flume speeds examined. The calibrated CFD model was then used for simulating a series of 210 scenarios using varying ring operating speeds over a range of flow depths and bed roughness heights. The numerical simulation results were then used to study the complex 3D turbulent flow conditions in the circular flume at NWRI, including velocity profiles, turbulence characteristics of flow and bed shear stress distributions.