The Effect of Six-Legged Concrete Elements on Hydraulic Jump Characteristics

Subject Areas : Journal of Water Sciences Research

Mahmood Shafai Bejestan ¹ , Maryam Khajavi ² , Azade Ghavamifar ³

1 - Professor, Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2 - Ph.D candidate, Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3 - Former M.Sc Student, Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Received: 2016-07-05 Accepted : 2016-11-23 Published : 2017-08-01

Keywords: hydraulic jump, Stilling basins, roughened bed, jump length, sequent depth,

Abstract :

In the present study, the six legged concrete (SLC) elements are placed at the bed of a flume downstream of a chute in different layouts, densities and number of longitudinal rows of SLC elements. Each test was run for different flow conditions (Froude numbers ranged 5.3 to 8.1). During each test, the water surface profile, the roller length and the jump length measured. Applying the experimental results, the sequent depth ratio and the dimensionless jump length calculated and compared to obtain the best layouts, the best densities and the minimum number of longitudinal rows of SLC elements. The results indicated that generally, the SLC elements can increase the shear force and consequently, reduce the jump length and the sequent depth of the jump. For the best layout, a linear type obtained when the SLC elements placed with 26% density. For the case of 100% density, the minimum longitudinal rows of SLC elements obtained to be equal to 21, or a basin 32% shorter than the smooth bed basin.