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EN
Hydrofoils are utilized as instruments to improve the hydrodynamic performance of marine equipment. In this paper, the motion of a 2D NACA0012 hydrofoil advancing in water near the free surface was simulated, and a mesh morphing-adjoint based optimizer was used to maximize its lift-to-drag ratio. Ansys-Fluent was used as a CFD solver, and a mesh-morphing tool was used as a geometry reconstruction tool. Furthermore, the Adjoint solver was applied to evaluate the sensitivities of the objective function to all solution variables. Defined control points around the geometry are design variables that move in an appropriate direction through shape sensitivity. The computational results were validated against available experimental data and published numerical findings. Subsequently, different hydrodynamic characteristics of the optimized hydrofoil were compared to those of the original model at different angles of attack of 3, 3.5, 4, 4.5, 5, 5.5, 6, and 6.5°, and optimized shapes were determined. It was observed that the shape of the optimized hydrofoil was totally dependent on the angle of attack, which produced different lift-to-drag ratios. It is also seen that among higher angles of attack at which improvement in the L/D ratio became steady, the drag coefficient was the lowest at 5°. Therefore, it can be concluded that the appropriate angle of attack for a hydrofoil installation on the ship hull is 5°. Further investigation was conducted concerning the evolution of shape optimization, sensitivity analysis, free surface elevation, flow characteristics, and hydrodynamic performance of the hydrofoil at a 5° angle of attack.
EN
The article presents an analysis of the wing-engine nacelle flow interference phenomenon on the example of a light twin-engine commuter aircraft. The problems of propulsion system integration with the wing in airplanes are now frequently the subject of advanced optimization research performed by aircraft manufacturers. The shape of the engine nacelle and its connection with the wing determines the quality of the flow around the wing in that area. This is important for high-lift devices placed at the wing trailing edge behind engine nacelle used during the take-off and landing process. Additionally the flow is effected by the disturbances generated by working propellers, the presence of air inlets and an exhaust system of the engine. The article presents a process of numerical optimization of an engine nacelle rear part shape. The main goal of the process was to eliminate the flow disturbances caused by the engine nacelle-wing interference phenomenon. During analysis, the Adjoint Solver method was used to designate nacelle body areas where modification should have the most important impact on the flow quality. The results obtained from adjoint solver were used in the process of finding the optimum shape of the rear part of the nacelle using a parametric geometry generator powered by Ansys Design Modeler and PARADES software. Comparative computational analysis for selected geometries of the engine nacelle was performed using commercial Ansys Fluent solver. Ansys Fluent is an advanced computational solver based on the finite volume method for solving the Navier-Stokes flow equations. Several dozen of geometric shapes were analysed in the optimization process of the nacelle rear part. The final result was the shape of the engine nacelle with correct flow without separation and vortex structures. The article presents results of calculations and visualization of the flow pattern for analysed cases.
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