Prediction of the dynamic pressure distribution in hydraulic structures using soft computing methods
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METHODOLOGIES AND APPLICATION
Prediction of the dynamic pressure distribution in hydraulic structures using soft computing methods Mehrshad Samadi1 • Hamed Sarkardeh2 • Ebrahim Jabbari1
Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Prediction of dynamic pressure distribution (P ) is a subject of great importance in the design and operation of the hydraulic structures. Flip buckets, using as hydraulic structures for dissipation of the excess energy outflow, are usually constructed at the end of the chute of the spillways. In this research, based on experimental studies of large hydraulic models, five well-known soft computing methods including artificial neural networks (ANN), gene expression programming (GEP), classification and regression trees (CART), M5 model tree (M5MT), and multivariate adaptive regression splines (MARS) approaches are examined. Mathematical expressions are obtained by these methods to predict P in flip buckets. Compared to ANN and GEP expressions, explicit formulas derived by CART, M5MT, and MARS demonstrated more straightforward calculations. In addition, linear and nonlinear equations are generated for better comparison with the outcomes of the proposed soft computing methods. The obtained results showed the high performance of the suggested soft computing methods for the prediction of P in flip buckets. It is found that the GEP approach culminated in more accurate results than other proposed soft computing methods and conventional linear and nonlinear regression techniques. Error measures in the testing stage showed that the formula provided by GEP with root mean square error (RMSE = 0.095), scatter index (SI = 13%), and mean absolute error (MAE = 0.073) has the best accuracy among the other predictive equations. Keywords Dynamic pressure distribution Hydraulic structures Soft computing methods
1 Introduction Flip buckets are constructed at the end of chute spillways and outlet conduits to dissipate the energy outflow from them. Pressure fluctuations are considered to be an
Communicated by V. Loia. & Ebrahim Jabbari [email protected] Mehrshad Samadi [email protected]; [email protected] Hamed Sarkardeh [email protected] 1
School of Civil Engineering, Iran University of Science and Technology (IUST), P.O. Box 16765-163, Narmak, Tehran, Iran
2
Department of Civil Engineering, Hakim Sabzevari University, Sabzevar, Khorasan Razavi Province, Iran
important topic in the design and operation of hydraulic structures. The significance of pressure fluctuations in hydraulic structures is of great importance in some aspects, including the possibility of uplift forcing, cavitation creation, material fatigue, and eventually destruction of the structure (Sobani 2014). Hence, the study of pressure fluctuations is essential for determining the safety and stability of the structure of flip buckets. The phenomenon of pressure fluctuations has oscillatory and random nature. Therefore, physical models
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