سید حامد معراجی

This study addressed the impact of variations in time parameters on the downstream bed of a culvert equipped with energy dissipators, with a focus on three specific parameters related to the energy dissipators. A total of nine experiments were conducted, utilizing energy dissipators over different time intervals. Among the most prominent findings of the study was that the highest rate of maximum scour depth was recorded during the interval of 0.03 to 0.062 times the equilibrium time. The scour hole deepened by more than 15% during that interval. Furthermore, minimal rate of increase in the maximum scour depth was determined within the time interval of 0.875 to 0.75 times the equilibrium time. During this specific time frame, the increase in the maximum scour depth was quantified to be less than 1%. The nondimensionalized area of scour holes was greater than their nondimensionalized volume in every test, which is indicative of the broadness of the scour holes. The maximum dimensionless scour area was found in the test lasting for a duration of 0.125 times the equilibrium time and the maximum scour volume was measured in the test lasting for a duration of 0.875 times the equilibrium time. Furthermore, the most substantial dimensionless sedimentation area and volume occurred in the test conducted in 0.75 times the equilibrium time te.