Anti-dunes に関する実験的研究

Abstract

Some experiments are conducted for the geometrical characteristics of anti-dunes andthe regime criteria of the case of the upper flow regime in an open channel with movablebed. And the comparison with many studies by various authors and these experimentsgives the following results.The Kennedy's equation is the most good agreement with experimental data for thewave length. The propagation velocity obtained by Kennedy, Gradowczyk and the author, which are analyzed by each different methods give the same results and these show agood agreement with measured one. And the analytical result by the author for the waveheight of the bed wave can be used for all flow regimes with sufficient accuracy.The author's experiments show that the effect of the grain-size is very remarkable forthe occurrence of anti-dunes and the region of the flat bed is wider as increase of the graindiamenter of bed materials. Though it made to he possible to predict the geometricalproperties of sand waves from the mean flow parameters with sufficient accuracy, all theoriesreported up to this time can not systematically explain the mechanism of the occurrenceof various bed configurations including the effect of the grain-size with the clear physicalhack ground. And it will he required the further studies.