Performance of transition model for predicting low aerofoil flows without/with single and simultaneous blowing and suction

Genç, Mustafa Serdar; Kaẏnak, Ünver; Yapıcı, Hüseyin

doi:10.1016/j.euromechflu.2010.11.001

Cited by 93 publications

(74 citation statements)

References 33 publications

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“…As previously discussed in the literatures, the flow separation and the laminar separation bubble affect the airfoils running with low Reynolds number [1][2][3][4][5][6][7][8]. The laminar separation bubbles are firstly separated from surface of airfoil and encounter with adverse pressure gradient [10].…”

Section: Qwurgxfwlrqmentioning

confidence: 99%

“…In the past time and nowadays, aerodynamic researches concentrated on low Reynolds number aerodynamics, transition and laminar separation bubble for efficiency of wind power or flight regime [1][2][3][4][5][6][7][8][9]. As it was mentioned, these flight regime or efficiency of wind power can be improved before the analysis and design of aerofoil operating in the low Reynolds number.…”

Section: Qwurgxfwlrqmentioning

confidence: 99%

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Flow characteristics over NACA4412 airfoil at low Reynolds number

Genç

Koca

Açıkel

et al. 2016

EPJ Web of Conferences

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$EVWUDFW In this study, the flow phenomena over NACA4412 were experimentally observed at various angle of attack and Reynolds number of 25000, 50000 and 75000, respectively. NACA4412 airfoil was manufactured at 3D printer and each tips of the wing were closed by using plexiglas to obtain two-dimensional airfoil. The experiments were conducted at low speed wind tunnel. The force measurement and hot-wire experiments were conducted to obtain data so that the flow phenomenon at the both top and bottom of the airfoil such as the flow separation and vortex shedding were observed. Also, smoke-wire experiment was carried out to visualize the surface flow pattern. After obtaining graphics from both force measurement experiment and hot-wire experiment compared with smoke wire experiment, it was noticed that there is a good coherence among the experiments. It was concluded that as Re number increased, the stall angle increased. And the separation bubble moved towards leading edge over the airfoil as the angle of attack increased.

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Section: Qwurgxfwlrqmentioning

confidence: 99%

Section: Qwurgxfwlrqmentioning

confidence: 99%

Flow characteristics over NACA4412 airfoil at low Reynolds number

Genç

Koca

Açıkel

et al. 2016

EPJ Web of Conferences

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“…Viscous effects, separated and vortical flows are more prevalent and separation bubbles, transition, and reattachment processes are very attractive and also little understood at low Re number aerodynamics [1]. At low Reynolds number flow conditions, some negative effects are occurred such as decreasing on lift, increasing on drag, reducing stability of the aircraft, vibration, and noise due to the laminar separation bubble [4][5][6][7][8][9][10][11]. Genç et al conducted an experimental [9] and numerical [11] studies over the NACA2415 aerofoil at various angles of attack and low Reynolds numbers.…”

Section: Introductionmentioning

confidence: 99%

“…The aerodynamic of low aspect-ratio wings have been extensively investigated by aerodynamic researches keen on low aspect ratio wings and low Reynolds numbers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Viscous effects, separated and vortical flows are more prevalent and separation bubbles, transition, and reattachment processes are very attractive and also little understood at low Re number aerodynamics [1].…”

Section: Introductionmentioning

confidence: 99%

Effect of tip vortices on flow over NACA4412 aerofoil with different aspect ratios

Genç

Özkan

Açıkel

et al. 2016

EPJ Web of Conferences

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Abstract. Effect of tip vortices on flow and laminar separation bubble over NACA4412 aerofoil at low Reynolds numbers and different angles of attack was investigated in detail by performing force and flow visualization via smoke wire technique. Experiments have been done at Reynolds number of 50000 and the wing model of aspect-ratio was 1 and 3, respectively. From the experimental results, the flow visualization results showed that tip vortices effect on the laminar separation bubble and the bubble reduces over the wing with low aspect ratio as the angle of attack increased. Moreover, it was noticed that stall angles decreased as aspect-ratio increased at the same Reynolds number.

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“…Previous works by the authors [11][12][13] have demonstrated an excellent accuracy of the four equations transition SST model, developed by Menter et al [14][15][16]. Furthermore, scientific literature underlines and demonstrates that, the use of transition turbulence models, at low Reynolds numbers [10,[17][18][19][20][21][22][23], is essential in obtaining an adequate CFD modeling of airfoil and rotor aerodynamic behaviors.…”

Section: Introductionmentioning

confidence: 99%

Transition turbulence model calibration for wind turbine airfoil characterization through the use of a Micro-Genetic Algorithm

Mauro

Lanzafame

Messina

et al. 2017

Int J Energy Environ Eng

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The aerodynamic characterization of airfoils is of crucial importance for the design and optimization of wind turbines. The present paper tries to provide an engineering methodology for the improvement of the accuracy and reliability of 2D airfoil computational fluid dynamics models, by coupling the ANSYS Fluent solver and a Micro-Genetic Algorithm. The modeling strategy provided includes meshing optimization, solver settings, comparison between different turbulence models and, mainly, the calibration of the local correlation parameters of the transition turbulence model by Menter, which was found to be the most accurate model for the simulation of transitional flows. Specifically, the Micro-Genetic Algorithm works by generating populations of the missing local correlation parameters. In doing so, it is possible to search for the minimization of the error in lift calculations. For each specific Reynolds number, the calibration was carried out only at the Angle of Attack where the lift drop occurs and the airfoil completely stalls. This new idea allowed for a relatively rapid and good calibration as demonstrated by the experimental-numerical comparisons presented in this paper. Only the experimental stall angle and the relative lift coefficient were, therefore, necessary for obtaining a good calibration. The calibration was made using the widely known S809 profile data. The correlation parameters, obtained as so, were subsequently used for testing on the NACA 0018 airfoil with satisfactory results. Therefore, the calibration obtained using the S809 airfoil data appeared to be reliable and may be used for the simulation of other airfoils. This can be done without the need for further wind tunnel experimental data or recalibrations. The proposed methodology will, therefore, be of essential help in obtaining accurate aerodynamic coefficients data. This will drastically improve the capabilities of the 1D design codes at low Reynolds numbers thanks to the possibility of generating accurate databases of 2D airfoil aerodynamic coefficients. The advantages of the proposed calibration will be helpful in the generation of more accurate 3D wind turbine models as well. The final objective of the paper was thus to obtain a fine and reliable calibration of the transition turbulence model by Menter. This was specifically made for an accurate prediction of the aerodynamic coefficients of any airfoil at low Reynolds numbers and for the improvements of 3D rotor models.

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Performance of transition model for predicting low aerofoil flows without/with single and simultaneous blowing and suction

Cited by 93 publications

References 33 publications

Flow characteristics over NACA4412 airfoil at low Reynolds number

Flow characteristics over NACA4412 airfoil at low Reynolds number

Effect of tip vortices on flow over NACA4412 aerofoil with different aspect ratios

Transition turbulence model calibration for wind turbine airfoil characterization through the use of a Micro-Genetic Algorithm

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