Abstract
In an open channel a translatory wave accompanied with a mass transfer is formed when a steady flow is turned into another steady flow by changing stream discharge at the upper end. This wave is called the “Cenveyance Wave” here.
In this study, transitional process of conveyance wave, whose Froude number is relatively small and on which rolling waves are not caused, is analyzed numerically. The Froude number is below about 1.5, when the Manning formula is used in friction term.
The results are:
(1) Positive conveyance waves, which are formed when the discharge is increased, are all transformed into uniformly progressive wave at the last stage.
With these numerical results, the conclu.sions of previous report are verified.
Negative conveyance waves, on the contrary, continue to be transformed and never become uniformly progressive waves.
(2) Characteristic features of conveyance waves are explained schematically throught all stages, that is, from the first stage to the last stage. Furthermore, no singularities are caused and found.
(3) Bore height, upper-end depth and wavelength turmed out to be apPropriate indexes for understanding the transitional process of the conveyance wave.
Effects of Fr0 and a for these indexes are examined by theoretical partial analysis, and their characteristic time-dependent features are explained to some extent.(Fr0: Froude number of initial uniform flow.α: change rate of discharge)
