Modeling of Scour Downstream of the Triangular Labyrinth Spillway Using Flow-3D Software

Ghamatloo, Amir; Abbasi, Saeed

doi:10.22075/jme.2025.36964.2814

Modeling of Scour Downstream of the Triangular Labyrinth Spillway Using Flow-3D Software

Document Type : Research Paper

Authors

Amir Ghamatloo

Saeed Abbasi

Faculty of Civil Engineering, University of Zanjan, Zanjan, Iran

10.22075/jme.2025.36964.2814

Abstract

In this paper, the results of scour depth (Ds) and scour pit length (Ld) are compared with the experimental results conducted by Elnikhely and Fathy at 4 different discharges, 0.007, 0.008, 0.009 and 0.010 m3/s. The dimensionless parameters are the ratio of scour depth to the depth of the outfall (Yt), i.e. Ds/Yt, and the ratio of scour pit length to the depth of the outfall, i.e. Ld/Yt. It is observed that with increasing discharge, the maximum values of the dimensionless ratios Ds/Yt and Ld/Yt have a decreasing trend. This is because with increasing discharge, the depth of the outfall increases. This research showed that the numerical model has a good ability to simulate the sediment transport and scour process downstream of the triangular convoluted spillway. The numerical results are in good agreement with the experimental results and the rate of change of the scour pit at the bottom of the spillway is close to zero. With increasing discharge, the maximum values of the depth and length of the scour pit have decreased. On average, the difference between the numerical and experimental results is less than 5%. It can be concluded that there is a good agreement between the results. Numerical simulation of physical phenomena allows for a more detailed study of the flow field, velocity vectors and pressure contours, which is also discussed in this article.

Keywords

Local scour

Energy dissipation

Jump characteristics

Numerical model

Flow-3D

Subjects

Civil Engineering – Hydraulic Structures

[1] Vice Presidency for Strategic Planning and Supervision. 2011. Guide to Methods for Calculating Local Scour. Publication 549.

[2] Dargahi, Bijan. "Scour development downstream of a spillway." Journal of hydraulic research 41, no. 4 (2003): 417-426.

[3] Mohammed, T. A., M. M. M. Noor, B. K. Huat, A. H. Ghazali, and T. S. Yunis. "Effect of curvature and end sill angle on local scouring at downstream of a spillway." International Journal of Engineering and Technology 1, no. 1 (2004): 96-101.

[4] Dey, Subhasish, and Arindam Sarkar. "Scour downstream of an apron due to submerged horizontal jets." Journal of hydraulic engineering 132, no. 3 (2006): 246-257.

[5] Dey, Subhasish, and Rajkumar V. Raikar. "Scour below a high vertical drop." Journal of Hydraulic Engineering 133, no. 5 (2007): 564-568.

[6] Alwan, Husam Hadi, Hayder HH Kamonna, and Noor Alaa Hashim. "Evaluation of local scour development downstream an apron of different angles for an ogee spillway." Kufa Journal of Engineering 7, no. 3 (2016): 1-12.

[7] Epely-Chauvin, G., G. De Cesare, and S. Schwindt. “Numerical Modelling of Plunge Pool Scour Evolution in Non-Cohesive Sediments.” Engineering Applications of Computational Fluid Mechanics 8, no. 4 (2014): 477–87.

[8] Sá Machado, L., M. M. C. L. Lima, R. Aleixo, and E. Carvalho. “Effect of the Ski Jump Bucket Angle on the Scour Hole Downstream of a Converging Stepped Spillway.” International Journal of River Basin Management 18, no. 3 (2020): 383–94.

[9] Yousefzadeh Podeh, F., M. Esmaeili Varaki, B. Shafiei Sabet, and S. Sahameddin Mahmoudi Kurdistani. “Experimental Study of the Effect of the Apron Installation on Reducing Scour Depth at the Downstream of Stepped Weirs with Labyrinth Sill.” Journal of Hydraulics 18, no. 1 (2023): 65–81. (in Persian).

[10] Abdi Chooplou, C., M. Ghodsian, D. Abediakbar, and A. Ghafouri. “An Experimental and Numerical Study on the Flow Field and Scour Downstream of Rectangular Piano Key Weirs with Crest Indentations.” Innovative Infrastructure Solutions 8, no. 5 (2023): 140.

[11] Dah-Mardeh, Arman, Gholamreza Azizyan, Mahmood Shafai Bejestan, Abbas Parsaie, and Seyed Hossein Rajaei. "Laboratory investigation of scour downstream of the Stepped spillway." (2023).

[12] Badaghi, Elnaz, Massoud Qudsian, and Chenour Abdi. “Investigation and Experimental Evaluation of Scour Downstream of A-Type Trapezoidal Key Overflow in Free and Submerged Flow.” Hydraulic Journal 18, no. 1 (2023): 1–18.

[13] Elghandour, E. H., A. A. Habib, M. R. Fahmy, and E. Eltohamy. “Investigation of Hydraulic Characteristics Downstream of Gabion Dams.” The Egyptian International Journal of Engineering Sciences and Technology, (2023)

[14] Yakhot, V., S. A. Orszag, S. Thangam, T. B. Gatski, and C. G. Speziale. “Development of Turbulence Models for Shear Flows by a Double Expansion Technique.” Physics of Fluids 4, no. 7 (1992): 1510–20.

[15] Ghasem Zadeh, F. Simulation of Hydraulic Problems in FLOW-3D. Tehran: Naavar Publications, 2015. (in Persian).

[16] Hedayatifar, M., and M. Pourlak. Fluid Dynamics Simulation with FLOW-3D. Tehran: Ati Nagar Publications, 2014. (in Persian).

[17] Elnikhely, Eman Aly, and Ismail Fathy. "Prediction of scour downstream of triangular labyrinth weirs." Alexandria Engineering Journal 59, no. 2 (2020): 1037-1047.

[18] Crookston, Brian Mark. “Labyrinth Weirs.” PhD diss., Utah State University, 2010