چكيده به لاتين
Pressure fluctuations in hydraulic jumps are one of the important features of turbulent flows that have adverse effects on the performance of stilling basins. In this study, the hydrodynamic pressures of the flow in type I and II stilling basins without an intermediate block have been analyzed.
To analyze the big data of the hydrodynamic pressures obtained from hydraulic models, it is necessary to use intelligent approaches to discover the hidden knowledge and the governing pattern in the data. Therefore, soft computing approaches including ANN, GEP, MARS models, and two decision tree algorithms, M5 and CART, have been used to estimate the dimensionless coefficient of pressure fluctuations. Evaluation of the resulting models showed that the MARS model is more accurate than other proposed equations.
In addition, there is always the possibility of outlier data among the hydrodynamic pressure data, taken from laboratory models, in laboratory works. Therefore, the combined intelligent approaches of the evolutionary algorithms including PSO, GA, and ABC and application of BOF, CS, and DB objective functions have been used to identify outlier data in type I and II stilling basins. Also, the spectral analysis method has been used for further analysis. The proposed approach optimizes the thickness of the concrete slab floor of stilling basins and reduces their thickness. In addition, by removing the outlier data, it is observed that the thickness of the concrete slab in the right and left axis of the stilling basins is almost the same, which is proportional to the physics of the phenomenon due to the symmetry of the studied stilling basins.
Furthermore, since in laboratory studies, it is hard and even impossible to simultaneously investigate the relationship between hydrodynamic pressures and velocity components in physical models, the numerical simulation approach has been used to solve this problem. Therefore, numerical simulation such as the LES turbulence model and VOF free surface model has been used to simulate hydrodynamic pressures and investigate the relationship between hydrodynamic pressures and velocity components. Based on the obtained results, the most inverse relationship is found between hydrodynamic pressures and the horizontal component of velocity and then between the former one and the vertical component of velocity. But no special relationship has been observed between the transverse component of velocity and pressure. It can be concluded that the approaches obtained from this research can help researchers to design safe and cost-effective hydraulic structures exposed to hydraulic jumps, especially stilling basins.
