Abstract
In this paper, the effect of quarter cylinder obstacles on hydraulic jump in a rectangular channel has been studied in the laboratory. The quarter-cylindrical obstacles with 2 and 3 cm diameter are considered and the effect of their position and height are studied in the hydraulic jump parameters such as location, energy dissipation and Froude number. The flume used in this research has six meter long, 20 cm wide and 30 cm height. The reason of quarter-cylindrical shape selection for obstacles is reduce the amount of erosion relative to other shapes such as rectangular and trapezoidal obstacles. The obstacles are installed at the end of the channel. Distance between the first obstacle and the beginning of the channel is constant. Totally, 44 tests have been carried out in this research. The results show that increasing distance between the obstacles to a certain amount, increases energy dissipation. But energy dissipation decreases for further distance. Furthermore, optimum s/r increases with increase in the obstacles height. Keywords: Energy Dissipation, Froude Number, Hydraulic Jump, Obstacle
Highlights
In order to prevent the damages caused by the huge extraordinaire energy of water in extra critical speeds and in order to destroy extra kinetic energy existing in such currents, it is generally required to use special structures called energy dissemination that are made in flow downstream
The effects of the barriers installed at the end of the canal on creating jump, the place jump is formed; the amount of energy dissipation and the changes of the primary Froude number were studied
barriers on the type of hydraulic jump, barriers with the height of r = 2,3 cm in different distances s were placed in the way of the flow and the changes in Froude number related to primary depth of hydraulic jump per different values of discharge and relative roughness (s/r) were measured as shown in Figures 5 and 6 respectively
Summary
In order to prevent the damages caused by the huge extraordinaire energy of water in extra critical speeds and in order to destroy extra kinetic energy existing in such currents, it is generally required to use special structures called energy dissemination that are made in flow downstream. When the jump occurs in a special point and its oversensitivity against deep flow fluctuations is restricted, the structures known as hydraulic jump inhibitors have to be used. Beirami and Hosseini studied the effect of distance between continued walls on the bed on controlling hydraulic jump. They showed that increase in the wall height has a reducing role of secondary depth and the length of whirlpool jump[2]. Gohari and Farhoudi did their experiments within Froude numbers 3 to 10 They saw that the secondary depth of jump on rough bed has a decrease as compared to channel with smooth bed and this reduction increases with the increase in the roughness’s8. The amount of energy dissipation is studied and the findings have been presented and analyzed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
