عنوان مقاله [English]
Bed topography downstream of the new hydraulic jump stilling basin (covered with six-legs elements) has been investigated in this study. Variation of maximum scour depth for different hydraulic conditions (Froude number ranged from 5.76 to 9.13) and three different sediment particle sizes was studied. The basin length, which was kept constant at all tests, was measured for maximum flow discharge. At this condition the maximum scour depth was measured which was found to be 61% less than that of maximum scour depth reported by other studies conducted for smooth bed basin. Increase of sediment particles from 0.95 mm to 2.23 can cause the scour depth to reduce by as much as 56%. In those tests which the jump length was less than the basin length, the scour depth was reduced significantly. For test with jump length to basin length ratio equal to 0.405, the scour depth shows reduction of 64% on an average. The upstream and downstream scour banks angles was measured for all tests which was to be equal to 6-24 degrees and 2-7 degrees respectively. The best fitted relation for dimensionless longitude bed profile also was obtained and presented.
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