MAXIMUM AND MEAN VELOCITIES AND ENTROPY IN OPEN-CHANNEL FLOW

The maximum velocity in a channel cross section is highlighted with respect to its information content and relation to the mean velocity and entropy parameter. Under a wide range of discharge and water depth, a channel section seems to have propensity to establish and maintain an equilibrium state that corresponds to a value of entropy parameter. The entropy parameter of a channel section can be determined from the relation between the mean and maximum velocities. A technique has been developed to determine the discharge from a velocity profile on a single vertical passing through the point of maximum velocity in a channel cross section. The technique is an efficient way to estimate the discharge in streams and rivers, that can be used to continuously update the flow resistance during an unsteady flow, to enhance a filtering scheme designed to reduce uncertainties in flow forecasting. The use of the constant value of entropy parameter predetermined for a channel section can simplify the discharge estimation.