Numerical prediction of rectangular open-channel flow by using large eddy simulation

Numerical prediction of a turbulent open-channel flow, which has an aspect ratio (=channel-width/flow-depth) of 6, was conducted by the use of a large eddy simulation (LES). In this study, the numerical model combined with I-equation model. The numerical results of time-averaged mean velocity and secondary currents are coincident with experimental data obtained by Nezu & Rodi(1985) with a laser Doppler anemometer.. The instantaneous flow fields in a cross section and horizontal planes were analyzed numerically. The instantaneous secondary currents were observed away from the side walls. The maximum value of instantaneous secondary currents is larger than 20% of the streamwise velocity.