Water Science and Engineering 2017, 10(1) 17-24 DOI:   http://dx.doi.org/10.1016/j.wse.2017.03.010  ISSN: 1674-2370 CN: 32-1785/TV

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multiple subvertical jets
plunge pool
Stefano Pagliara
Michele Palermo
Article by Stefano Pagliara
Article by Michele Palermo

Scour process caused by multiple subvertical non-crossing jets

Stefano Pagliara *, Michele Palermo

DESTEC-Department of Energy, Systems, Territory and Construction Engineering, University of Pisa, 56122 Pisa, Italy


The scour process induced by plunging jets is an important topic for hydraulic engineers. In recent decades, several researchers have developed new strategies and methodologies to control the scour morphology, including different jet arrangements and structures located in the stilling basin. It has been found that multiple jets can cause less scouring than single plunging jets. Based on this evidence, this study aimed to investigate the equilibrium morphology caused by multiple non-crossing jets. A dedicated laboratory model was built and experimental tests were carried out under different combinations of jet inclination angles, by varying the tailwater level and the virtual crossing point location, which was set below the original channel bed level. It was experimentally shown that the equilibrium scour morphology depends on the jet discharge, the differences in non-crossing jet inclination angles, the downstream water level, and the distance of the virtual crossing point from the original channel bed level. In particular, the last parameter was found to be one of the most influential parameters, because of the resulting flow patterns inside the water body. Furthermore, the analysis of experimental evidence allowed for a complete and detailed classification of the scour hole typologies. Three different scour typologies were distinguished and classified. Finally, based on previous studies, two novel relationships have been proposed to predict both the maximum scour depth and length within a large range of hydraulic and geometric parameters.

Keywords multiple subvertical jets   plunge pool   scour   spillway   tailwater  
Received 2016-10-01 Revised 2016-12-31 Online: 2017-01-31 
DOI: http://dx.doi.org/10.1016/j.wse.2017.03.010
Corresponding Authors: Stefano Pagliara
Email: s.pagliara@ing.unipi.it
About author:


Ade, F., Rajaratnam, N., 1998. Generalized study of erosion by circular horizontal turbulent jets. Journal of Hydraulic Research. 36(4), 613–635. http://dx.doi.org/10.1080/00221689809498612.
Aderibigbe, O.O., Rajaratnam, N., 1996. Erosion of loose beds by submerged circular impinging vertical turbulent jets. Journal of Hydraulic Research. 34(1), 19–33. http://dx.doi.org/10.1080/00221689609498762.
Canepa, S., Hager, W.H., 2003. Effect of jet air content on plunge pool scour. Journal of Hydraulic Engineering. 129(5), 358–365. http://dx.doi.org/10.1061/(ASCE)0733-9429(2003)129:5(358).
Chiew, Y.-M., Lim, S.-Y., 1996. Local scour by a deeply submerged horizontal circular jet. Journal of Hydraulic Engineering. 122(9), 529–532. http://dx.doi.org/10.1061/(ASCE)0733-9429(1996)122:9(529).
Dey, S., Sarkar, A., 2006. Scour downstream of an apron due to submerged horizontal jets. Journal of Hydraulic Engineering. 132(3), 246–257. http://dx.doi.org/10.1061/(ASCE)0733-9429(2006)132:3(246).
Faruque, M.A.A., Sarathi, P., Balachandar, R., 2006. Clear water local scour by submerged three-dimensional wall jets: Effect of tailwater depth. Journal of Hydraulic Engineering. 132(6), 575–580. http://dx.doi.org/10.1061/(ASCE)0733-9429(2006)132:6(575).
Hoffmans, G.J.C.M., 1998. Jet scour in equilibrium phase. Journal of Hydraulic Engineering. 124(4), 430–437. http://dx.doi.org/10.1061/(ASCE)0733-9429(1998)124:4(430).
Li, L.X., Liao, H.S., Li, T.X., 2006. A hybrid model for simulating velocity field of a river with complex geometry plunged by multiple jets. Journal of Hydrodynamics.18(6), 752–759. http://dx.doi.org/10.1016/S1001-6058(07)60017-1.
Mih, W.C., 1982. Scouring effects of water jets impinging on non-uniform streambeds. In: Proceedings of Conference Applying Research to Hydraulic Practice. ASCE, Jackson, pp. 270–279.
Mih, W.C., Kabir, J., 1983. Impingement of water jets on nonuniform streambeds. Journal of Hydraulic Engineering. 109(4), 536–548. http://dx.doi.org/10.1061/(ASCE)0733-9429(1983)109:4(536).
Pagliara, S., Hager, W.H., Minor, H.-E., 2006. Hydraulics of plane plunge pool scour. Journal of Hydraulic Engineering. 132(5), 450–461. http://dx.doi.org/10.1061/(ASCE)0733-9429(2006)132:5(450).
Pagliara, S., Amidei, M., Hager, H., 2008. Hydraulics of 3D plunge pool scour. Journal of Hydraulic Engineering. 134(9), 1275–1284. http://dx.doi.org/10.1061/(ASCE)0733-9429(2008)134:9(1275).
Pagliara, S., Palermo, M., 2008. Plane plunge pool scour with protection structures. Journal of Hydro-Environment Research. 2(3), 182–191. http://dx.doi.org/10.1016/j.jher.2008.06.002.
Pagliara, S., Roy, D., Palermo, M., 2010a. Scour due to crossing jets at fixed vertical angle. Journal of Irrigation and Drainage Engineering. 137(1), 49–55. http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000275.
Pagliara, S., Roy, D., Palermo, M., 2010b. 3D plunge pool scour with protection measures. Journal of Hydro-Environment Research. 4(3), 225–233. http://dx.doi.org/10.1016/j.jher.2009.10.014.
Pagliara, S., Palermo, M., Carnacina, I., 2011. Scour process due to symmetric dam spillways crossing jets. International Journal of River Basin Management. 9(1), 31–42. http://dx.doi.org/10.1080/15715124.2010.549090.
Pagliara, S., Palermo, M., Roy, D., 2012a. Stilling basin erosion due to vertical crossing jets. Journal of Hydraulic Research. 50(3), 290–297. http://dx.doi.org/10.1080/00221686.2012.669534.
Pagliara, S., Roy, D., Palermo, M., 2012b. Closure to "Scour due to Crossing Jets at Fixed Vertical Angle" by Stefano Pagliara, Dipankar Roy, and Michele Palermo. Journal of Irrigation and Drainage Engineering. 138(4), 390–391. http://dx.doi.org/10.1061/(ASCE)0733-9437(2007)133:3(289.2).
Pagliara, S., Palermo, M., 2013. Analysis of scour characteristics in presence of aerated crossing jets. Australian Journal of Water Resources. 16(2), 163–172. http://dx.doi.org/10.7158/13241583.2013.11465412.
Pagliara, S., Hassanabadi, L., Kurdistani, S.M., 2015. Clear water scour downstream of log deflectors in horizontal channels. Journal of Irrigation and Drainage Engineering. 141(9). http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000869.
Rajaratnam, N., Berry, B., 1977. Erosion by circular turbulent wall jets. Journal of Hydraulic Research. 15(3), 277–289. http://dx.doi.org/10.1080/00221687709499648.
Rajaratnam, N., 1981. Erosion by plane turbulent jets. Journal of Hydraulic Research. 19(4), 339–358. http://dx.doi.org/10.1080/00221688109499508.
Rajaratnam, N., Aderibigbe, O., 1993. A method for reducing scour below vertical gates. Proceedings of the Institution of Civil Engineers: Water and Maritime Engineering. 101(2), 73–83. http://dx.doi.org/10.1680/iwtme.1993.23588.
Sarkar, A., Dey, S., 2007. Effect of seepage on scour due to submerged jets and resulting flow field. Journal of Hydraulic Research. 45(3), 357–364. http://dx.doi.org/10.1080/00221686.2007.9521769.

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