Simulation of Hydraulic Processes in Open Channels

Abstract

Techniques combining the deterministic and stochastic methods have been developed to compute and simulate various hydraulic processes in open channels, such as the three-dimensional distribution of flow velocity, steady and unsteady flows, flow resistance, secondary currents, and unsteady dispersion. The deterministic approach, using a curvilinear coordinate system based on the velocity distribution of flow, is used to deal with the basic hydrodynamic part of analysis. The stochastic approach is used to treat the irregular channel geometry that tends to cause uncertainties in simulated hydraulic processes in open channels. The techniques can be used to simulate the three-dimensional velocity distribution of (primary) flow, unsteady dispersion, and sediment transport, secondary currents, steady and unsteady flows, and flow resistance (Manning’s n.) In computing an unsteady flow it was found that the use of mean cross sections, without the geometrical irregularity of channel, causes errors in the peak and recession part of computed hydrographs, although it has the advantages of being simple and insensitive to uncertain Manning’s n.