Experimental investigating effect of Froude number on hydraulic parameters of vertical drop with supercritical flow upstream

Document Type : Research Article

Authors

1 Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.

2 Civil Engineering Department, Faculty of Engineering, University of Maragheh, Maragheh, Iran.

3 Graduate Student, Maraghe University, Maragheh, Iran

Abstract

The supercritical flow as the inflow at upstream of the vertical drops can produce a considerable impact, destruction and erosion at the downstream of drops influence by fall and collision. Therefore in this study, with the aim of evaluation and prediction of the general behavior of hydraulic parameters in vertical drops with the supercritical flow at upstream, 55 experiments were carried out with various discharges and Froude numbers. The experimental results indicated that in the supercritical flows, by increasing the relative critical depth and Froude numbers, the relative length of drop, the relative length of splashing and the relative total length of the drop were increased. However, by increasing the relative critical depth and Froude number, the relative depth of the pool initially increases and then decreases, and the relative energy loss is initially reduced and then increased. By increasing the Froude number at a constant relative critical depth, the relative length of the drop, the relative length of splashing, the relative total length of drop and the relative energy loss increases, and relative depth of the pool decreases. Also, in a constant Froude number, by increasing the relative critical depth, the relative length of drop, the relative length of splashing, the relative total length of the drop and relative depth of the pool increase, and the relative energy loss decreases. Meanwhile, the results of the present study with the larger range of Froude number were compared with the previous studies and were studied the reasons for the agreement or disagreement.

Keywords

Main Subjects

References

[1]Chamani M. and Beirami, M.K. (2002). “Flow characteristics at drops”, Journal of Hydraulic Engineering, 791-788(8)128 .
[2]Gill M.A. (1979) “Hydraulics of rectangular vertical drop structures”, Journal of Hydraulic Research, 302-289 (4)17.
[3]Bakhmeteff M.W. (1932). “Hydraulics of open channels”, McGraw-Hill book company, Inc, New York and London.
[4]Moore W.L. (1943). “Energy loss at the base of a free overfall”, Transactions of the American Society of Civil Engineers, 1360-1343 (1)108.
[5]White M.P. (1943) “Discussion of Moore”, ASCE 108 1364-1361.
[6]Rand W. (1955) “Flow geometry at straight drop spillways”, In Proceedings of the American Society of Civil Engineers, 13-1 (9)81.
[7]Chanson H. (1995). “Hydraulic design of stepped cascades, channels, weirs and spillways”.
[8]Rajaratnam N. and Chamani M.R. (1995) “Energy loss at drops”, Journal of Hydraulic Research, 384-373 (3)33.
[9]Chamani, M.R.  Rajaratnam, N. and Beirami, M.K. (2008). “Turbulent jet energy dissipation at vertical drops”, Journal of hydraulic engineering, 1535-1532 (10)134.
[10]Esen I.I.  Alhumoud J.M. and Hannan K.A. (2004) “Energy Loss at a Drop Structure with a Step at the Base”, Water international 529-523 (4)29
[11]Hong Y.M. Huang, H.S. and Wan S. (2010) “Drop characteristics of free-falling nappe for aerated straightdrop spillway”, Journal of Hydraulic Research -125 (1)48 129.
[12]Kabiri-Samani, A.R. Bakhshian, E. and Chamani, M.R. (2017) “Flow characteristics of grid drop-type dissipators”, Flow Measurement and Instrumentation, 306-298 54.
[13]Sharif M. and Kabiri-Samani A. (2018) “Flow regimes at grid drop-type dissipators caused by changes in tail-water depth”, Journal of Hydraulic Research, 12-1 (4)56.
[14]Tokyay N.D and Yildiz D. (2007).  “Characteristics of free overfall for supercritical flows”, Canadian Journal of Civil Engineering, 169-162 2)34.
[15]Liu S.I. Chen J.Y.  Hong, Y.M. Huang H.S. and Raikar R.V. (2014) “Impact Characteristics of Free Over-Fall in Pool Zone with Upstream Bed Slope”, Journal of Marine Science and Technology 486-476 (4)22.
[16]Chanson H. and Toombes L. (1998) “Supercritical flow at an abrupt drop: Flow patterns and aeration”, Canadian Journal of Civil Engineering 966-956 (5)25.
[17]Rajaratnam N. (2008). “Turbulent jets Elsevier”, 5.
[18]Hager W.H. and Bremen R. (1989). “Classical hydraulic jump: sequent depths”, Journal of Hydraulic Research, 585-565 (5)27.
[19]Chow V.T.  (1959). “Open Channel Hydraulics”, Mc Graw Hill, New York.
[20]Chanson H. and Gualtieri C. (2008). “Similitude and scale effects of air entrainment in hydraulic jumps”, Journal of Hydraulic Research, 44-35 (1)46.
[21]M. Mossa, A. Petrillo, H. Chanson, Tailwater level effects on flow conditions at an abrupt drop, Journal of Hydraulic Research, 51-39 (2003) (1)41. 
Amirkabir Journal of Civil Engineering
Volume 52, Issue 7
October 2020
Pages 1765-1782

Files

Share

How to cite

Statistics