Study of characteristics of submerged hydraulic jump on bed roughness and adverse slopes

Control of hydraulic jump to reduce damage to the structures of downstream is one of the issues of interest to researchers. Although several researches have been conducted on the application of rough bed to control submerged jump but, any study has not been published on the simultaneous application of the adverse slope, bed roughness and the positive step. In this research, the effect of different adverse slopes, bed roughness and positive step height were simultaneously investigated on characteristics of submerged hydraulic jump in Froude numbers from 4 to 10 and submerge ratio from 0.1 to 1.5. The results showed that in each special Froude number, the length of submerged jump and its relative energy loss are more and less than these specifications for free hydraulic jump; respectively. In addition to, with increasing the submerge ratio, the average energy loss and the submerged jump length decreased 10 and 33%; respectively as compare to the classical state. Also, the thickness of the dimensionless boundary layer of submerged jump was 0.37. On the other hand, the shear force coefficient (ε) was calculated 4.44 times more than the classic condition.