Calculation of oscillating turbulent flows in open channels

An alternating-direction implicit type finite difference method is used to calculate the vertical structure of oscillatory turbulent flows in two-dimensional open channels. The free surface elevation is determined by using, for each time step, the Leap-Frog method is the first half step and an implicit method at the second half step. The turbulent shear stress is calculated with the k-epsilon turbulence model. Turbulent flow in a laboratory estuary model with one end closed is simulated with the numerical model, and the results are compared with the corresponding flume and field measurements. The influence of frequency and roughness is investigated. The results indicate that the time and space variation of the velocity field and the phase log between the surface slope and the horizontal velocity can be predicted satisfactorily in oscillatory turbulent flows.