Understanding and modeling a dam breaching process is an essential investigation, because it aims to minimize the flood’s hazards, and its impact on people and structures, using suitable mitigation plans. In the current study, three-dimensional numerical modeling is carried out using the FLOW-3D HYDRO program to investigate the impact of various factors, including the dam grain size materials, crest width, inflow discharge, and tail water depth on the dam breach process, particularly the peak outflow, and the erosion rate. The results show that changing the grain size of the dam material from fine sand to medium and coarse sand leads to an increase in the peak outflow discharge by 16.0% and the maximum erosion rate by 20.0%. Furthermore, increasing the dam crest width by 40% leads to a decrease in the peak outflow by 3.0% and the maximum erosion rates by 4.50%. Moreover, increasing the inflow discharge by 25.0% increases the peak outflow by 23.0% and the maximum erosion rates by 21.0%. Finally, increasing the tail water depth by 50.0% leads to decreasing the peak outflow by 4.50% and the maximum erosion rate by 43.0%. The study findings are considered of high importance for dam design and operation control. Moreover, the results can be applied for the optimum determination of the crest width and tail water depth that leads to improving the dam stability.

Recently, many countries have sought to obtain sustainable energy from different sources. This study’s primary objective is to determine ways to optimize the advantages of water structures, especially ski-jump spillways, within the hydropower sector. A ski-jump spillway is a type of energy dissipation structure that relies on projectile principles, causing scour holes in the downstream bed. To convert the flow energy into hydroelectric power, the wheel turbine is mounted in the spillway bucket. The turbine’s impact on total hydraulic energy reduction, power generation, and downstream scour was evaluated, alongside optimizing blade design (number and shape) for peak performance. To conduct this research, a numerical 3D model was created using FLOW-3D HYDRO. Adding turbines to the ski-jump spillway is a promising modification, increasing total hydraulic energy reduction by approximately 22.10% and decreasing the maximum scour depth under the investigated conditions. It was discovered that increasing the number of turbine blades from five to 10 results in a 2.77% increase in total hydraulic energy reduction under the investigated conditions. This study represents a starting point toward harvesting flow energy that would otherwise be dissipated, in contrast to most researchers in this field, who focus primarily on reducing hydraulic energy without recovering it.

Scouring is a problem that should be considered while designing bridges; scour around inclined piles in the presence of waves has rarely been researched. However, in reality, many inclined braces are used for aesthetic reasons, which alters the flow properties depending on their exposure to the flow field. The purpose of this work is to numerically examine the flow behavior and local scour evolution around inclined piles downstream under wave conditions. The effect of three inclination angles (10°, 20° and 30° downstream flow direction) is numerically investigated compared with the vertical circular pile. A three-dimensional hydro-morphological turbulent model is used. The reliability of the flow and scour estimates was verified with remarkable accuracy. The results reveal that the inclination affects both the intensity and location of the downflow, as well as the pattern of the horseshoe vortex upstream of the pile. Vertical piles have deeper scour than inclined ones, owing to the decrease of downflow in front. Strong horseshoe vortices arise upstream of inclined pier scouring variance patterns between inclined piles and vertical piles. The scour reduction increases with increasing the inclination angle. The Keulegan-Carpenter number (KC) has a slight effect on the scour reduction due to the three-inclination angle. The scour reduction due to the inclination with wave conditions is lower than the reduction at current conditions.

Contaminants can reach the excavation site and lead to groundwater contamination. The present research investigates the effect of using sheet piles for controlling the migration of contaminants to excavation sites that require high-quality groundwater, taking into consideration changing concentrations of contaminants and changing soil surface depth downstream of the sheet piles. The arrival time of contamination to reach under the sheet piles and the time for reaching contamination to the excavation site were studied. Additionally, the effect of using two different sources of contaminants with different concentrations on the mixing time between them through groundwater was investigated. Two modules, SEEP/W and CTRAN/W of the numerical model Geo-Studio are used. The parameters considered are depths of excavation, depths of sheet piles, upstream water heads, hydraulic conductivity of the soil, and concentrations of contaminants. The results show that the arrival times under the sheet piles and to the excavation level increase by decreasing the hydraulic conductivity of the soil, upstream water head, and with decreasing the excavation depth. The mixing time of contaminants decreases with increasing the upstream water head and the hydraulic conductivity and with increasing the depth of the soil surface level behind the sheet pile. Dimensionless design charts are presented to determine the effect of changing the soil surface level downstream of the sheet piles on the arrival time for contamination to reach under the sheet piles and to the excavation surface.

Understanding and accurately predicting the outflow hydrograph from embankment dam breaches is essential for managing the associated flood hazard and improving emergency preparedness. This work simulates the breaching process using a high-resolution 3D computational fluid dynamics (CFD) model, a critical natural hazard for earth-fill dams under overtopping conditions. The model was validated against the experimental data, showing high accuracy in predicting breach development and failure timing. A parametric analysis was performed to assess the influence of the initial breach geometry on erosion dynamics. The results indicated a high sensitivity, while increasing the breach width by 5% led to an average 11% increase in the erosion rate, and decreasing the depth by 5% caused an average 16.5% rise. To enhance predictive capabilities for this hazard, a multilayer neural network (MLNN) was trained on the CFD-generated dataset. The network utilized breach geometry and time as inputs to forecast the peak outflow and erosion rate, achieving excellent accuracy (RMSE = 0.019, R² = 0.99). This integrated modeling strategy combines data-driven learning with physics-based simulation and demonstrates its effectiveness for laboratory-scale dam breach modeling. This approach is a step toward more efficient surrogate-based tools for flood risk analysis, though its extension to full-scale dams and varied material properties requires additional validation and scaling analyses beyond the scope of this work.

This study uses numerical simulations in ANSYS Fluent to analyze the flow characteristics of open channel confluences. The primary objective is to assess the accuracy and predictive performance of three widely used turbulence models: the standard k–ε, the realizable k–ε, and the k–ω SST models. Simulations were performed under steady-state conditions. The results were validated against experimental data. Comparative analysis based on roots mean square error (RMSE) and flow behavior evaluation shows that all models can capture the main flow structures. However, the k–ω SST model demonstrated superior agreement with the experimental results, exhibiting the lowest RMSE and providing the most accurate representation of the flow field. These results demonstrate the significance of model selection in simulating complex hydraulic interactions such as those occurring in channel confluences. The choice of turbulence model plays a crucial role in capturing these complex phenomena with reasonable computational effort. This study contributes to the growing body of research focused on optimizing turbulence model selection for simulating open channel confluence flows.