The Sea-wave Slot-cone Generator (SSG) wave-energy device is a type of electric energy converting structure that converts energy from sea waves, and which is designed and installed based on wave-overtopping in areas. Most of the previous studies have evaluated SSG systems based on hypothetical waves, considering the system geometry variations. However, it is important to consider the real wave conditions. This paper presents the results of a numerical study to investigate the performances of an SSG system in the context of the Persian Gulf and Oman Sea, where there is a strong need for renewable energies. The computational fluid dynamic (CFD) code Flow-3D was applied. First of all, available experimental data were applied to calibrate and evaluate the accuracy of the numerical model. Then, the real wave conditions on the coasts of the Persian Gulf and Oman Sea were imposed on the JONSWAP spectrum for the numerical modeling. Results of the study demonstrated that the hydraulic efficiency of the SSG system in the Persian Gulf and Oman Sea was low for wave heights lower than 0.5 m. The nominal efficiency of the system was relatively more than 60% for wave heights higher than 1 m; thus, the performance of the SSG system was suitably evaluated. Finally, the numerical results demonstrated that the most optimal conditions, with a nominal efficiency of 97%, were obtained for incident waves that had a height of 2 m and a period of 5.6 s. In this case, the hydraulic performance of the system was maximum.

Flip buckets are a common configuration for side channel spillways. Similar to other spillways, the flip bucket or ski jump has its disadvantages, among which the scour hole downstream due to the flip bucket jet is the most important. The structure safety and stability may be influenced by the scour holes generated at the downstream side of bucket type energy dissipators. This study has employed an experimental model in order to examine the sediment scour created at the end of flip bucket energy dissipators at various flow rates and tail water depths. A total of 45 experiments were performed under different conditions. The experimental invistigation was conducted at the hydraulic laboratory of Shahid Chamran University in Iran. The main objective of this research was to identify the maximum depth of sediment scour ( ) and the maximum distance of sediment scour hole ( ) from the structures. The results showed that the maximum depth of scour and its distance from the structure increased by increasing discharge. The results of experimental models show that, at the downstream depths ( ) of 0.2 and 0.3 m, the stack was formed by the scouring at the upstream side of the hole, and at a depth of 0.1 m, this stack was transferred to the area after the scour hole. This could be explained by the fact that at downstream depths of 0.2 and 0.3 m, the rolling flow moved from the bottom upwards in the opposite direction of the water flow and sequestrated the sediments upstream. According to Equation Mean Absolute Relative Error(MARE) proposed relation based on laboratory studies has MARE of about 34.2%.

The jet flipped from flip buckets hits the dam’s downstream side as a free jet with an immense amount of energy, leading to bed erosion. Erosion of river bed materials downstream of dams could affect the performance of dams or power plants by altering the tailwater depth, rendering proper designs of controlling structures or erosion reduction methods highly indispensable in this regard. Hence, the hydrodynamic performance of A‐Jacks concrete armor units in controlling scour was examined in this study. A‐Jacks armors are applicable as a flexible protection without environmental risks often for bed erosion control. The desirable functionality of A‐Jacks armors depends on the flow hydrodynamic parameters such as velocity profile variations (U/U_B), the Reynolds stresses ( and τ_v′w′), and the skin friction coefficient (C_f) created as a consequence of using A‐Jacks armors on beds. The size of A‐Jacks elements can have a role in increasing the flow turbulence to a certain depth so that after the impact of the flow with A‐Jacks armor, the vortices’ intensity as well as the shear stress affecting the bed gradually decreases. The results of the numerical model suggest that the surge in the flow turbulence energy dissipation downstream of flip buckets significantly mitigates the underlying conditions of scouring phenomena, which is evidence of A‐Jacks armors’ acceptable performance in scaling down scour depths.

Underwater explosion is a subject that has been paid attention to by many researchers. In this study the underwater explosion phenomena under shockwave loading is explored by numerical method. For this purpose, by modeling a marine pipe buried in the water by ABAQUS software, the effect of the shock wave and the damages were assessed. Then using the laboratorial results, the fluid-structure interaction and shock wave loading and its results were analysed. Finally, it was concluded from numerical modeling that the highest levels of strain on the pipe buried in the water under underwater explosion and shock wave loading occur in the ending parts of the pipe in both sides and away from explosion field.

Converging ogee spillways are employed to help mitigate the natural hazards, e.g. coincidental floods. However, due to complicated nature of converging spillway hydraulics; determining governing relationships is difficult and the outcomes of the accessible conventional models is not accurate. This study concentrates on the ability of Support Vector Machine (SVM) as a Meta-model technique for estimating discharging capacity of converging ogee spillways. In this regard, two different experimental datasets were applied for simulating. To consider the models developed, two scenarios with various input combinations were dealt while scenario1 consist of two parts. Scenario1a considers only free flow condition, scenario1b considers just submerged flow properties, and scenario2 considers general flow condition including free and submerged flow dataset. The obtained results confirmed that SVM is capable of estimating the discharge capacity. It was found that for prediction discharge capacity, the SVMs performed much more accurate in free flow stage (Scenario1a) in comparison with other situations. Sensitivity analysis indicated that the ratio of the entire upstream head to the height of spillway (𝐻 / 𝑝) and downstream apron position (𝑑+ℎ𝑑 / 𝐻 ) under free flow condition, spillway geometry parameter (𝐿2/𝐿′.𝐿𝑐ℎ) on submerged flow condition, and the ratio of the entire upstream head to design head (𝐻 / 𝐻𝑑) and 𝐿2 / 𝐿′.𝐿𝑐ℎ in general flow condition plays a key role in simulating process. Comparisons among SVMs and existing relationships demonstrated that SVM models produced better outcomes.