In this paper, the flow in the vicinity of RECTANGULAR side ORIFICEs placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε,and RNG k-ε,turbulence models are employed to predict turbulence flow. According to the results obtained from the numerical modeling, the RNG k-ε,turbulence model has higher accuracy than the standard k-ε, . The analysis of the numerical modeling results proved that this model forecasts the discharge coefficient of side weirs with suitable accuracy. On the other hand, the mean absolute percent error (MAPE) is calculated equal to 12. 204%. Also, the maximum pressure is simulated near the main channel bed. Moreover, the minimum pressure is estimated near the flow free surface. Regarding the numerical simulations, the maximum turbulence energy state occurs near the inlet of the side ORIFICE and by increasing the side ORIFICE dimensions the flow field turbulence energy value increases.

The dynamic behavior of a very LARGE RECTANGULAR floating structure is considered. The structure is modelled as a plate with free edges. Two different thicknesses are considered for the model. The Mindlin plate theory is used to formulate the structure behavior. Natural frequencies, mode shapes, and stress resultants of the structure are predicted by using finite element method. For this purpose, a MATLAB code is written. The same analysis is performed by using the ANSYS software. The results of these two analysis are compared with each other and with the available results in the literature, where close agreement is observed. Therefore, the written finite element code is found to be acceptable for prediction of the dynamic behavior of very LARGE RECTANGULAR floating structures in early stages of design.

The results of LARGE-eddy simulations are presented to illustrate the flow structures generated by the interaction of synthetic jets with a crossflow. The coupled calculations involving the internal flow of the actuator cavity and the external flow are performed using the ANSYS-Fluent software. The influence of the ORIFICE shape (round ORIFICE and RECTANGULAR ORIFICEs with aspect ratio of 6, 12, or 18) on the evolution of coherent structures is analyzed, and the effects of the jet-to-crossflow velocity ratio (0.5, 1.0, or 1.5) on the turbulent flow behavior are examined. The results show that the first vortex ring shed from the RECTANGULAR ORIFICE lip behaves as a plate-like vortex. The horseshoe vortex and first vortex ring are followed by a trailing jet in the case of a round ORIFICE, but this configuration is rarely identified when the ORIFICE is RECTANGULAR. For the RECTANGULAR ORIFICE with an aspect ratio of 18, the plate-like vortex splits into vortex filaments that become interwoven with the center of the synthetic jet. In general, at the same characteristic velocity, the round-ORIFICE synthetic jet has a stronger capacity for normal penetration into the crossflow, whereas the RECTANGULAR-ORIFICE synthetic jet with a LARGE aspect ratio develops closer to the wall. For the RECTANGULAR ORIFICE with a LARGE aspect ratio, the development of the synthetic jet is restricted to a small region near the wall at a small jet-to-crossflow velocity ratio.

The energy that can be extracted from the ocean is inexhaustible. An oscillating water column (OWC) is a wave energy converter that extracts this energy. A numerical investigation has been conducted by altering relative opening (α) and ORIFICE ratio (τ) to assess the maximal energy of a land-fixed RECTANGULAR-based OWC model in a nonlinear wave field. The power of OWC has also been evaluated by the wave steepness (H/L) alteration. The numeric analysis has been imposed to obtain the optimal power using Fluent software in a three-dimensional tank. Validation of the present numeric model’s result correlates with the printed empirical data. The Finite Volume Method (FVM) solves RANS equations, and the relevant waves are generated at the inlet of the numerical tank by the inlet velocity approach. The efficiency (η) increases with relative openings (α) increase. The efficiency (η) decreases with wave steepness (H/L) increase. The η reaches the optimum shown in the study at H/L = 0. 02 and τ = 1. 03% for entire values of α. The excellent energy of around 71. 3% is attained at α =75% and H/L = 0. 02. This study is a highly relevant source of information that finds the optimal efficiency of a land-fixed RECTANGULAR base OWC and gives prior knowledge of the performance of OWC before the real-life experiment.