Acoustic Control of Flow Over NACA 2415 Aerofoil at Low Reynolds Numbers

Genç, Mustafa Serdar; Açıkel, Halil Hakan; Akpolat, M. Tuğrul; Özkan, Gökhan; Karasu, İlyas

doi:10.1007/978-3-319-34181-1_31

Cited by 9 publications

(6 citation statements)

References 26 publications

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“…studied flow and LSB over the airfoil at low Reynolds numbers 8 and its control using leading edge slat, 9 suction and/or blowing, 10 and acoustic forcing. 11,12 They observed that the short bubble occurred at lower angles of attack, while the long bubble was seen at higher angles of attack as in Rinioie and Takemura’s study. 13 They concluded that as the angle of attack and Reynolds number increased, the LSB shrunk and moved towards the leading edge of airfoil 8 like in Tani’s study.…”

Section: Introductionmentioning

confidence: 61%

Interaction of tip vortex and laminar separation bubble over wings with different aspect ratios under low Reynolds numbers

Genç

Özkan

Özden

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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In present study, aerodynamics of a NACA4412 wings with aspect ratio of 1 and 3 was considered experimentally at Reynolds numbers of 2.5 × 104, 5 × 104 and 7.5 × 104. Studies for AR = 1 wing showed that stall was delayed and extra (vortex) lift was obtained, because separation bubble got smaller in both chordwise and spanwise axes with effect of wing-tip vortices. Oil-flow experiments at higher angles of attack clarified the reason for vortex lift obtained from AR = 1 wing. However, there was an increase in drag coefficient as well as vortex lift, and stall delayed due to tip vortex. Turbulence intensity distributions pointed out location of the transition to turbulence; Reynolds stress and turbulence kinetic energy distributions indicated shear layer. Furthermore, in experiments of AR = 3 wing, the viscous forces and leading edge vortices were effective at Re = 2.5 × 104 and Re = 5 × 104, but flow over the wing at Re = 7.5 × 104 acted as a 2D flow. After α = 12°, bubble burst and stall consisted abruptly because effectiveness of 3D flow decreased over wing. Strouhal (St) numbers of vortex shedding frequencies in wake of AR = 3 wing had a certain difference from St = 0.17/sinα curve at lower angle of attack (α = 0° − 10°) due to separation bubble, but AR = 1 wings showed that St numbers were near St = 0.17/sinα curve.

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Section: Introductionmentioning

confidence: 61%

Interaction of tip vortex and laminar separation bubble over wings with different aspect ratios under low Reynolds numbers

Genç

Özkan

Özden

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…In addition, stationary and non-stationary AC-DBD plasma actuators were used to improve flow over the NACA0024 airfoil [20]. Acoustic flow control for a NACA 2415 airfoil was carried out at low Reynolds number and it was revealed that the acoustic control effect on the separation bubble was decreased while Reynolds number increased [21]. Another study related to controlling the flow in different ways was implemented using a flexible flap for NACA 0012 airfoil.…”

Section: Introductionmentioning

confidence: 99%

Passive Flow Control of Ahmed Body using Control Rod

Şumnu

2022

Int. J. Automot. Mech. Eng.

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In the current study, numerical analysis of passive control flow with a control rod for Ahmed body is performed at different slant angles and velocities and placed rod locations on the slant surface. The aim of the study is to improve aerodynamic performance by preventing flow separation on the slant surface of Ahmed body using a control rod. This passive flow control method uses a control rod that has not been applied for simplified ground vehicles before. Therefore, it can be said that this study is a new example in point of a passive flow control application for Ahmed body. The solution of the study is performed by using the Computational Fluid Dynamics (CFD) method. The solutions are firstly performed for baseline geometry, and the results are compared with experimental data reported in the literature for validation. CFD solutions are carried out by means of the ANSYS and RNG k- turbulence model is used to simulate flow-field since it captures the effect of turbulent flow. The solutions used a control rod with a 20 mm diameter performed at a dimensionless location (X/L=0.057 and 0.153) for Ahmed body. The results are presented visually in the figures, and drag coefficient values are also given in Table format. It is concluded that the rod application is useful for some specified slant angles and velocities since flow separation delays and suppresses the slant surface. The maximum drag reduction is achieved at about 6.153% at a slant angle of 35° and 20 m/s velocity of air, and location of control rod of 0.057, while the minimum drag reduction is about 1.048% at slant angle of 25° and velocity of air at 40 m/s and location of control rod of 0.153.

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“…To alleviate the moment forces on a blade owing to wind force, blade mass and centrifugal force, and to decrease the negative effects of such as noise and vibration (Koca et al, 2018;Genç et al, 2018), the blade must be produced with advanced production technologies using well-developed materials. Or the flow over the wind turbine blade must be controlled (Genç et al, 2008(Genç et al, , 2016Genç, 2016, 2018;Genç et al, 2019Genç et al, , 2020. Thus, optimization of the structural performance of the blade is vital.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective structural optimization of a wind turbine blade using NSGA-II algorithm and FSI

Özkan

Genç

2021

AEAT

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Purpose Wind turbines are one of the best candidates to solve the problem of increasing energy demand in the world. The aim of this paper is to apply a multi-objective structural optimization study to a Phase II wind turbine blade produced by the National Renewable Energy Laboratory to obtain a more efficient small-scale wind turbine. Design/methodology/approach To solve this structural optimization problem, a new Non-Dominated Sorting Genetic Algorithm (NSGA-II) was performed. In the optimization study, the objective function was on minimization of mass and cost of the blade, and design parameters were composite material type and spar cap layer number. Design constraints were deformation, strain, stress, natural frequency and failure criteria. ANSYS Composite PrepPost (ACP) module was used to model the composite materials of the blade. Moreover, fluid–structure interaction (FSI) model in ANSYS was used to carry out flow and structural analysis on the blade. Findings As a result, a new original blade was designed using the multi-objective structural optimization study which has been adapted for aerodynamic optimization, the NSGA-II algorithm and FSI. The mass of three selected optimized blades using carbon composite decreased as much as 6.6%, 11.9% and 14.3%, respectively, while their costs increased by 23.1%, 29.9% and 38.3%. This multi-objective structural optimization-based study indicates that the composite configuration of the blade could be altered to reach the desired weight and cost for production. Originality/value ACP module is a novel and advanced composite modeling technique. This study is a novel study to present the NSGA-II algorithm, which has been adapted for aerodynamic optimization, together with the FSI. Unlike other studies, complex composite layup, fiber directions and layer orientations were defined by using the ACP module, and the composite blade analyzed both aerodynamic pressure and structural design using ACP and FSI modules together.

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Acoustic Control of Flow Over NACA 2415 Aerofoil at Low Reynolds Numbers

Cited by 9 publications

References 26 publications

Interaction of tip vortex and laminar separation bubble over wings with different aspect ratios under low Reynolds numbers

Interaction of tip vortex and laminar separation bubble over wings with different aspect ratios under low Reynolds numbers

Passive Flow Control of Ahmed Body using Control Rod

Multi-objective structural optimization of a wind turbine blade using NSGA-II algorithm and FSI

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