Recognizing of the best different artificial intelligence method for determination of local scour depth around group pie
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ORIGINAL PAPER
Recognizing of the best different artificial intelligence method for determination of local scour depth around group piers in equilibrium time Arash Adib 1 & Syed Hossein Tabatabaee 1 & Abdolgafour Khademalrasoul 1 & Mohammad Mahmoudian Shoushtari 1 Received: 2 November 2018 / Accepted: 16 July 2020 # Saudi Society for Geosciences 2020
Abstract Unlike calculation of scour depth around of a single pier, estimation of scour depth around group piers is a complex problem. In this research, four types of artificial neural networks (ANNs) were applied multi layer perceptron (MLP), radial basis function (RBF), neuro fuzzy inference system (ANFIS), and support vector machine (SVM). The inputs of ANNs were coordinates of considered points in the channel (X, Y), size of pier, flow depth, flow discharge, flow velocity, and critical velocity for inception of sediment transport. The trained methods were momentum and Levenberg–Marquardt (LM) training methods. Also, genetic algorithm (GA) was applied for optimization of MLP and RBF. Two group piers were used (three circular piers and three square piers) in a channel with stable flow conditions, scouring of clear water, and uniform bed particles (with D50 = 1.31 mm). Outputs of different ANNs (scour depth) were compared with observed data using of performance criteria correlation coefficient (R), mean square error (MSE), and mean absolute error (MAE). For circular piers, between square piers and behind of gear square pier, the best ANN is RBF-GA, while in front of first square pier, the best ANN is MLP-GA. The best ANNs have two hidden layers, and their training method is the Levenberg–Marquardt (LM). The values of R, MSE, and MAE of RBF-GA are 0.997, 1.66 mm2, and 0.9 mm, and the values of R, MSE, and MAE of MLP-GA are 0.997, 2.55 mm2, and 1.16 mm. Also, the sensitive analysis shows that threshold velocity (Uc) is the most effective factor on scour depth Keywords Local scouring . Group piers . MLP-ANN . RBF-ANN . ANFIS . SVM
Introduction Local scour around single pier is a phenomenon that was studied by many researcher and hydraulic engineers in different hydraulic laboratories and research centers. But few studies have been done about local scour around group piers. Many parameters can affect on local scour around group piers, which include the approaching flow characteristics (steady or unsteady flow conditions, flow velocity, and flow depth), the geometry of the pier (width, shape, and orientation to the flow direction), bed sediment particles (size, density, sediment load), and fluid properties (density and viscosity). Responsible Editor: Amjad Kallel * Arash Adib [email protected] 1
Civil Engineering Department, Engineering Faculty, Shahid Chamran University of Ahvaz, Ahvaz, Iran
A number of performed researches about local scour around group piers include Ataie-Ashtiani and Beheshti (2006), Zounemat-Kermani et al. (2009), Amini et al. (2012, 2014), Baghbadorani et al. (2018), Hamidi and Siadatmousavi (2018), Hosseini and Amini (2015), Liao et al. (2018
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