Unsteady RANS Simulations of Strong and Weak 3D Stall Cells on a 2D Pitching Aerofoil

Liu, Dajun; Nishino, Takafumi

doi:10.3390/fluids4010040

Cited by 3 publications

(4 citation statements)

References 39 publications

(58 reference statements)

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“…A low free-stream turbulence level was applied to match the wind tunnel characteristics, so the stream turbulence intensity was selected as less than 0.1% [19,30]. Also, the SIMPLE algorithm [19,22,[30][31][32][33][34] for pressure-velocity coupling and upwind second-order method was employed to discretize the pressure, momentum and turbulence transport equations. A sufficiently time step of 1 × 10 −4 was used to achieve Courant-Friedrichs-Lewy (CFL) number lower than 1, and the results were converged when the scaled residual was less than 1 × 10 −6 .…”

Section: Numerical Methods and Governing Equationsmentioning

confidence: 99%

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Fatahian

Nichkoohi

Salarian

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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In the present study, the effect of hinge position (H) has been numerically investigated to find the appropriate position for improving the aerodynamic performance of the NACA 0012 flapped airfoil. In addition, perpendicular and tangential suctions have been applied to control the flow separation and enhance the aerodynamic performance over the NACA 0012 flapped airfoil at each different hinge positions. The simulations were carried out at a Reynolds number of 5 × 10 5 (Ma = 0.021) based on two-dimensional incompressible unsteady Reynolds-averaged Navier-Stokes calculations to determine the adequate hinge position. The turbulence was modeled using the shear stress transport k-ω turbulence model. The effect of perpendicular suction (θ jet = − 90°) and tangential suction (θ jet = − 30°) was computationally studied over NACA 0012 flapped airfoil for five different hinge positions (H = 0.7c, 0.75c, 0.8c, 0.85c and 0.9c) and a flap deflection (δ f) of 15°. Based on the results, the hinge position significantly affects the aerodynamic performance of the airfoil. The lift coefficient increased clearly as the hinge position moved to the trailing edge of the airfoil. Using perpendicular suction caused to increase the lift coefficient and decrease the drag coefficient. Consequently, the maximum value of the lift-to-drag ratio (C L /C D) for perpendicular and tangential suctions was achieved about 35.8% and 25.1% higher than that of the case without suction at an angle of attack of 12° and H = 0.9c. Also, the effect of perpendicular suction was more considerable compared to the tangential suction. This caused a reduction in the size of the recirculation zone from 0.5 to 0.09 of the airfoil chord length and also transferred it from 1.13 to 1.18 of the airfoil chord length.

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Section: Numerical Methods and Governing Equationsmentioning

confidence: 99%

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Fatahian

Nichkoohi

Salarian

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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“…D x denotes the cross-diffusion term of x. The dissipation and the generation terms are defined as follows: [37,38]:…”

Section: Governing Equations and Turbulence Modelmentioning

confidence: 99%

Comparative study of flow separation control using suction and blowing over an airfoil with/without flap

et al. 2019

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This study mainly focused on the comparison of the effect of single and simultaneous suction and blowing jets on the aerodynamic performance of an airfoil with/without flap to evaluate the most effective flow control configuration using computational fluid dynamics (CFD) method. Moreover, the effect of applying single and simultaneous jets have been conducted on delaying and controlling the flow separation. The results were obtained using two-dimensional incompressible Unsteady Reynolds-Averaged Navier-Stokes (URANS), and the turbulence was simulated with SST k-x turbulence model. Also, different parameters including two jet locations (L jet), three jet velocity ratios (R jet), three jet angles (h jet) and three flap deflections (d f) were analyzed to find the most effective case of applying flow control jets to delay the boundary layer separation. It was concluded that applying a single suction jet and simultaneous suction and blowing jets on the flapped airfoil was more effective to improve the lift-to-drag ratio (C L /C D) than applying these jets to the without flap case. The maximum value of C L /C D was achieved by single suction jet for the without flap case which was equal to 73.7. The maximum increment of stall angle over the without flap airfoil and flapped airfoil was obtained by applying single suction jet, which increased the stall angle from 14°to 20°and 14°to 16°for the suction angle of-90°a nd suction velocity ratio of 0.15, respectively.

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“…These equations are called model equations because they are used to study the properties of solutions to more complex partial differential equations. Thus, the heat equation can be considered as a model for other partial differential equations, e.g., the Navier-Stokes equations [10][11][12]. All considered model equations have analytical solutions under certain boundary and initial conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Of the many existing finite-difference methods for solving partial differential equations, this article describes mainly those methods that have properties characteristic of a whole class of similar methods. Some finite-difference methods useful for solving equations are not given, since they are like those described by Khakimzyanov and Chernyy [12] and Anderson et al [13].…”

Section: Introductionmentioning

confidence: 99%

Several different ways to increase the accuracy of the numerical solution of the first order wave equation

Madaliev,

Orzimatov,

Abdulkhaev

et al. 2024

BIO Web Conf.

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The article presents several different ways to increase the accuracy of the numerical solution of differential equations. The comparison of schemes with different accuracy for the first order wave equation problem is presented. The schemes of the first order of upwind scheme, the second order of accuracy of McCormack, the third order of accuracy of Warming–Cutler–Lomax, and the scheme of the fourth order of accuracy of Abarbanel–Gotlieb–Turkel were applied. The condensed computational grids for the McCormack scheme are used, and the results using an adaptive grid for the McCormack scheme were compared.

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Unsteady RANS Simulations of Strong and Weak 3D Stall Cells on a 2D Pitching Aerofoil

Cited by 3 publications

References 39 publications

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Comparative study of flow separation control using suction and blowing over an airfoil with/without flap

Several different ways to increase the accuracy of the numerical solution of the first order wave equation

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