Abstract
In this study, local scour occurring downstream from a nozzle with and without plates formed in cohesionless materials was investigated experimentally. The experiments were performed to determine scour geometry, maximum scour depth, and the effect of aeration on scour for water jets impinged obliquely into the downstream pool. Dimensionless variables affecting the scour were determined as densimetric Froude number, dimensionless impingement length, and the ratio of densimetric Froude number to dimensionless impingement length. Experiments were conducted for three nozzle diameters with plates, three nozzle diameters without plates, two different impingement lengths, and three different exit velocities. The results of the experiments showed that the use of the plates in the nozzle, jet impact velocity, jet shape, jet expansion, jet impingement length, and air entrainment rate were critical parameters for scour geometry. As a result, it was found that the jets from a nozzle with plates entrained more air bubbles into the impingement pool than jets from nozzles without plates, thereby decreasing maximum scour depth by spreading the scour over a larger area. This was evident by increasing the impingement length. In addition, scour equations were obtained to determine maximum scour depth, ridge height, and scour hole length from experimental data.

















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Abbreviations
- A :
-
Section area of nozzle (L2)
- d :
-
Nozzle diameter (L)
- D :
-
Bed sediment diameter (L)
- D c :
-
Diameter of reduction pipe (L)
- D 15.9 :
-
15.9% Of sediment diameter (L)
- D 50 :
-
50% Of sediment diameter (L)
- D 84.1 :
-
84.1% Of sediment diameter (L)
- Δ m :
-
Maximum ridge height (L)
- ε :
-
Scour depth (L)
- ε m :
-
Maximum scour depth (L)
- E :
-
Erosion parameter (-) (F0/\(\surd\)(H/d))
- θ :
-
Impingement angle ( angle that jet makes with the water surface) (°)
- F0 :
-
Densimetric Froude number (-) (U0/(\(\sqrt {g\left( {\frac{\Delta \rho }{\rho }} \right)D_{50} }\))
- g :
-
Acceleration due to gravity (LT−2)
- ρ :
-
Mass density of water (ML−3)
- h :
-
Drop height (L)
- h k :
-
Thickness of sediment layer (L)
- H :
-
Impingement length (L)
- M 0 :
-
Momentum flux of jet (MLT−2)
- Re:
-
Jet Reynolds number (-) (\({\text{Re}} = \frac{{U_{0} .d}}{\nu }\))
- t :
-
Time (T)
- T :
-
Temperature (°C)
- t d :
-
Tailwater depth (L)
- U 0 :
-
Jet exit velocity (LT−1)
- Δx :
-
Distance from point of impingement to location of maximum depth (L)
- x :
-
Distance from the location of maximum erosion in the plane of symmetry (L)
- x 1 :
-
Distance from maximum scour to back side edge of scour hole (L)
- x 2 :
-
Distance from maximum scour to location where ε = 0 (L)
- x 3 :
-
Distance from location of maximum scour to top of ridge (L)
- x 1 + x 2 :
-
Maximum scour hole length (L)
- ‘ :
-
Measurement at asymptotic state
- υ :
-
Kinematic viscosity (L2T−1)
- ρ s :
-
Mass density of sediment (ML−3)
- Δρ :
-
Relative mass density (-)
- σ g :
-
Uniformity coefficient (-)
- Q w :
-
Water discharge (L3T−1)
- Q a :
-
Air entrainment rate (L3T−1)
- q :
-
Unit discharge(L3L−1 T−1
References
Aderibigbe O, Rajaratnam N (1996) Erosion of loose beds by submerged circular impinging vertical turbulent jets. J Hydraul Res 34(1):19–33
Ade F, Rajaratnam N (1998) Generalized study of erosion by circular horizontal turbulent jets. J Hydraul Res 36(4):613–633
Bagatur T, Sekerdag N (2003) Air-entrainment characteristics in a plunging water jet system using rectangular nozzles with rounded ends. Water SA 29(1):35–38
Canepa S, Hager WH (2003) Effect of jet air content on plunge pool scour. J Hydraul Eng 129(5):358–365
Chakravarti A, Jain RK, Kothyari UC (2013) Scour under submerged circular vertical jets in cohesionless sediments. ISH J Hydraul Eng 20(1):32–37
Chiew YM, Lim SY (1996) Local scour by a deeply submerged horizontal circular jet. J Hydraul Eng 122(9):529–532
Dey S, Bose SK, Sastry GLN (1995) Clear water scour at circular piers: a model. J Hydraul Eng 121(12):869–876
Dong C, Yu G, Zhang H, Zhang M (2020) Scouring by submerged steady water jet vertically impinging on a cohesive bed. Ocean Eng 196:106781
Emiroglu ME, Baylar A (2003) Role of nozzles with air holes in air entrainment by a water jet. Water Qual Res J Can 38(4):785–795
Farhoudi J, Smith KVH (1985) Local scour profiles downstream of hydraulic jump. J Hydraul Res 23(4):343–358
Fritz HM, Hager WH (1998) Hydraulics of embankment weirs. J Hydraul Eng 124(9):963–971
Gu L, Ni F, Xu L, and Zhang H (2015) An experiment of sand beds eroded by submerged plane jets. Int Conf on Appl Mech and Mechatronics Eng
Hager WH, Schleiss AJ, Boes RM, Pfister M (2019) Hydraulic engineering of dams, CRC Press
Hou J, Zhang L, Gong Y, Ning D, Zhang Z (2016) Theoretical and experimental study of scour depth by submerged water jet. Adv in Mech Eng 8(12):1–9
Kartal V (2018) Investigation of effect of nozzle type on scour geometry in water jets. Msc Thesis. Ins of Sci, Firat University, Elazıg, Turkey
Khaple S, Hanmaiahgari PR, Gaudio R, Dey S (2017) Interference of an upstream pier on local scour at downstream piers. Acta Geophys 65(1):29–46
Martino RG, Ciani FG, Paterson A, Piva MF (2019) Experimental study on the scour due to a water jet subjected to lateral confinement. Eur J Mech/B Fluids 75:219–227
Mason PJ (1989) Effects of air-entrainment on plunge pool scour. J Hydraul Res 115(3):385–399
Mazurek KA, Rajaratnam N (2005) Erosion of sand beds by obliquely impinging plane turbulent air jets. J Hydraul Res 43(5):567–573
Pagliara S, Hager WH, Minor HE (2006) Hydraulics of plane plunge pool scour. J Hydraul Eng 132(5):450–461
Pagliara S, Palermo M (2013) Rock grade control structures and stepped gabion weirs: Scour analysis and flow features. Acta Geophys 61(1):126–150
Pagliara S, Palermo M (2017) Scour process caused by multiple subvertical non-crossing jets. Water Sci Eng 10(1):17–24
Palermo M, Pagliara S, Bombardelli FA (2020) Theoretical approach for shear-stress estimation at 2D equilibrium scour holes in granular material due to subvertical plunging jets. J Hydraul Eng 146(4):04020009
Rajaratnam N (1976) Turbulent Jets. Elsevier Publishing Co, Amsterdam
Rajaratnam N, Beltaos S (1977) Erosion by impinging circular turbulent jets. ASCE J Hydraul Div 103(10):1191–1205
Rajaratnam N, Berry B (1977) Erosion by circular turbulent wall-jets. J Hydraul Res 15(3):277–289
Rajaratnam N, Diebel M (1981) Erosion below culvert-like structures. Sixth Canad Hydrotec Conf. 469–484
Rajaratnam N, Aderibigbe O, Pochylko D (1995) Erosion of sand beds by oblique plane water jets. Water Maritime Energy 112:31–38
Rajaratnam N, Mazurek KA (2002) Erosion of a polystyrene bed by obliquely impinging circular turbulent air jets. J Hydraul Res 40(6):709–716
Rouse H (1939) Criteria for similarity in the transportation of sediment. Iowa Inst of Hydraul Res Univ of Iowa 20:33–49
Samma H, Khosrojerdi A, Rostam-Abadi M, Mehraein M, Cataño-Lopera Y (2020) Numerical simulation of scour and flow field over movable bed induced by a submerged wall jet. J Hydroinform 22(2):385–401
Sarkar A, Dey S (2004) Review on local scour due to jets. Int J of Sed Res 19(3):210–239
Tastan K, Kocak PP, Yildirim N (2016) Effect of the bed-sediment layer on the Scour caused by a jet. Arab J for Sci Eng 41(10):4029–4037
Tafarojnoruz A, Gaudio R, Calomino F (2012) Bridge pier scour mitigation under steady and unsteady flow conditions. Acta Geophys 60(4):1076–1097
Xu W, Deng J, Qu J, Liu S, Wang W (2004) Experimental investigation on influence of aeration on plane jet scour. J Hydraul Eng 130(2):160–164
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Communicated by Michael Nones, Ph.D. (CO-EDITOR-IN-CHIEF)/Subhasish Dey, PhD; FNA; FASc;FNASc; FNAE (ASSOCIATE EDITOR).
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Kartal, V., Emiroglu, M.E. Local scour due to water jet from a nozzle with plates. Acta Geophys. 69, 95–112 (2021). https://doi.org/10.1007/s11600-020-00521-1
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DOI: https://doi.org/10.1007/s11600-020-00521-1