Experimental Study on the Geometric Effects of the Baffle Blocks in Stilling Basin on the Hydraulic Jump Characteristics Downstream of Smooth and Stepped Chutes

Document Type : Research Paper


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

2 University of Zanjan, Zanjan, 45371 - 38791, Iran

3 MSc Student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.


Hydraulic jump phenomenon is a rapid variation in flow conditions that occurs for dissipation of the kinetic energy of the flow in downstream of the hydraulic structures in stilling basins. The aim of this study is to investigate flow characteristics of stepped and smooth chute and the effects of block geometry on the hydraulic jump characteristics in the stilling basin USBR III. Experiments were conducted on the stepped chute and they were compared with smooth chute as well as stilling basin and baffle blocks and end sill in different geometry shapes to test the hydraulic behavior of different hydraulic conditions. The results were compared with stilling basin without block. The results of comparing the two types of chutes showed that in stepped chute, the air entrainment inception locations a positioning further upstream than the smooth chute due to the turbulence of the flow on the steps. The energy dissipation and Darcy roughness coefficient in stepped chute increases by 10% and 15.6% on average compared to smooth chute, respectively, which indicates the appropriate hydraulic performance of stepped chute compared to smooth type. Results showed that increasing the Froude number and height of the baffle blocks caused decreasing sequent depths ratio and the jump length by 22.12 and 36 percent, respectively, compared to classical jump. It is believed that the main reason was raising the rate of secondary flows and flow resistance due to the baffle blocks in stilling basin. The energy dissipation increased by 24 percent, compared to the classical jump and further increase in high Froude number.


Agha Majidi, R. and Nozari, A. H. (2020). Laboratory Study of SimultaneousCoarse-gradient Roughness and Positive Slope on Hydraulic Jump Length in Classical Stilling Basin: Water Engineering, 7(4), 281-291. (In Farsi)
Asadi, F. Fazloula, R. and Emadi, A. (2016). Investigation the characteristics of hydraulic jump in a rough bed condition using a physical model: Journal of Water and Soil Conservation, 23(5), 295-306. (In Farsi)
Chow, V. T. (1959). Open-channel hydraulics: McGraw-Hill civil engineering series.
Dastourani, M. Esmaili, K. and Khodashenas, S.R. (2016). The impact of water rectangular jet angel on the characteristics of hydraulic jump: Journal Water and Soil Cons, 23(3), 225-238. (In Persian)
Daneshfaraz, R. Ghaderi, A. Di Francesco, S. and Khajei, N. (2021). Experimental study of the effect of horizontal screen diameter on hydraulic parameters of vertical drop: Water Supply, 21(5), 2425-2436.
Daneshfaraz, R. Bagherzadeh, M. Ghaderi, A. Di Francesco, S. and Asl, M. M. (2021). Experimental investigation of gabion inclined drops as a sustainable solution for hydraulic energy loss: Ain Shams Engineering Journal, 12(4), 3451-3459.
Daneshfaraz, R. ASL, M. M. and Bagherzadeh, M. (2021). Experimental Investigation of the Performance of Inclined Gabion Drop Equipped with a Horizontal Screen: Iranian Journal of Soil and Water Research, 52(1), 81-93. (In Farsi)
Ead, S. A., & Rajaratnam, N. (2002). Hydraulic jumps on corrugated beds: Journal of Hydraulic Engineering128(7), 656-663.
Eshkou, Z., Dehghani, A.A. and Ahmadi, A. (2018). Forced hydraulic jump in a diverging stilling basin using angled baffle blocks: Journal of Irrigation and Drainage Engineering, ASCE, 144 (8), 06018004. (In Farsi)
Esmaili, K. and Abrishami, J. (2001). Hydraulic Jump over Negative Slopes with Negative Steps: Journal of Advanced Materials in Engineering, 19(2), 97-110. (In Farsi)
Ghaderi, A. Dasineh, M. Aristodemo, F. and Ghahramanzadeh, A. (2020). Characteristics of free and submerged hydraulic jumps over different macroroughnesses: Journal of Hydroinformatics, 22(6), 1554-1572.
Ghaderi, A. Dasineh, M. Aristodemo, F. and Aricò, C. (2021). Numerical simulations of the flow field of a submerged hydraulic jump over triangular macroroughnesses: Water, 13(5), 674.
Ghaderi, A. and Abbasi, S. (2021). Experimental Study of Energy Dissipation over Stepped Spillway with Appendance Elements on the Steps: Iranian Journal of Irrigation and Drainage, 15(3), 494-509. (In Farsi)
Karimi Chahartaghi, M. Nazari, S. and Babarsad, M. S. (2020). Investigating the Effects of the Block Geometries and Sidewall Divergences on the Local Scour Downstream of Baffled Chute Spillways: Advances in Civil Engineering. (In Press)
Dasineh, M., Ghaderi, A., Bagherzadeh, M., Ahmadi, M., and Kuriqi, A. (2021). Prediction of Hydraulic Jumps on a Triangular Bed Roughness Using Numerical Modeling and Soft Computing Methods: Mathematics, 9(23), 3135.
Jam, M. Mardasht, A. and Talebbeydokhti, N. (2014). Evaluation of Hydraulic Jump on Dentate Blocks Stilling Basin: Journal of Hydraulics, 9(1), 1-10.
Minaei, G. A. Ghodsian, M. and Mehraein, M. (2016). Experimental investigation of hydraulic jump in stilling basin with stepped sill: Modares Civil Engineering journal, 16(1), 145-155. (In Farsi)
Najandali, A. Esmaili, K. and Farhoudi, J. (2012). The Effect of Triangular Blocks on the Characteristics of Hydraulic Jump: Journal Water and Soil, 26(2), 282 - 289. (In Farsi)
Peterka, A. J. (1958). Hydraulic design of stilling basins and energy dissipaters engineering monograph No. 25: US Bureau of Reclamation, Denver Colorado.
Pagliara, S. and Palermo, M. (2015). Hydraulic jumps on rough and smooth beds: aggregate approach for horizontal and adverse-sloped beds: Journal of Hydraulic Research, 53(2), 243-252.
Rajaratnam, N. (1968). Hydraulic jumps on rough beds. Trans. Eng. Inst. Canada, 11(A-2), 1-8.
Salami Asl, S. Fathi, A. and Ghomeshi, M. (2018). Effect of the Artificial Bed Roughness’s Shape on Hydraulic Jump’s Characteristics: Irrigation Sciences and Engineering, 41(2), 19-31. (In Farsi)
Shojaeian, Z. Dalir, A. H. Farsadizadeh, D. and Salmasi, F. (2011). Investigation of Hydraulic Jump Characteristics in Divergent Rectangular Sections on Inverse Slope: Water and Soil Science, 21(3), 49-60. (In Farsi)
Taghinia, A. Asghari Pari, S. A. Shafai Bejestan, M. and Ahmadianfar, I. (2021). The effect of energy dissipation due to outflow water jet from floor and end of stilling basin on hydraulic jump: Journal of Hydraulics, 16(3). (In Farsi)
U.S.B.R. 1955. Resarch Studies on Stilling Basins. Energy Dissipators and Associated Appurtenances. U.S. Bureau of Reclamation: Hydraulic Laboratory Report No. Hyd-399.