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Shape optimization of a submerged 2D hydrofoil and improvement of its lift-to-drag ratio using CFDbased mesh morphing-adjoint algorithm

Nazemian Amin, Ghadimi Parviz, Ghadimi Aliakbar

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2022

nr 70 (142)

27--40

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.

Experimental determination of aerodynamic characteristics of the plane's wing with the volume generators

Lemko O. L., Molodchyk A., Predachenko K.

Prace Instytutu Lotnictwa

2016

Nr 4 (245)

79--86

This paper is devoted to the results of studies in a wind tunnel model aircraft mounted with the vortex generators on the wing leading edge. The article presents away to improve the aerodynamic characteristics with vortex generators on the leading edge in the direct flow. It is shown that the vortex generators increase the lift force and the critical angle of attack due to the impact of large-scale vortices on the flow separation. Experimental data of studies of the wing in the wind tunnel showed rationality of use of volume generators - there usage enlarges the range of flight angles of attack and significantly increases lift-to-drag ratio.

Niniejsza praca poświęcona jest wynikom badań w tunelu aerodynamicznym modelu samolotu wyposażonemu w generatory wirów na krawędzi natarcia skrzydła. W artykule przedstawiono sposób na poprawę właściwości aerodynamicznych samolotu z generatorami wirów na krawędzi natarcia w bezpośrednim strumieniu powietrza. Wykazano, że generatory wirów prowadzą do zwiększenia siły nośnej i krytycznego kąta natarcia z powodu wpływu dużych wirów na rozdzielenie przepływu. Dane doświadczalne badania skrzydła w tunelu aerodynamicznym wykazały, racjonalność wykorzystania generatorów wirów. Wykorzystanie powiększa zakres kątów natarcia i znacznie zwiększa współczynnik siły nośnej.