Modeling the increase in aerodynamic efficiency for a thick (37.5% chord) airfoil with slot suction in vortex cells with allowance for the compressibility effect

Исаев, С. А.; Baranov, P. A.; Sudakov, A. G.; Ermakov, A. M.

doi:10.1134/s1063785015010253

Cited by 10 publications

(2 citation statements)

References 5 publications

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“…On the other hand, the semi-circular profile can be consid-ered as a thick (50% of the chord) profile. In this respect, interest in this profile is to find perspective aerodynamic shapes of integrated vehicles with flow control by vortex cells [4][5][6]. The present work applies the data on flow with periodic vortex structures near a cir-cular cylinder at Re = 50000 [7][8][9] and on turbulent flow around a thin (12% of the chord) NACA0012 airfoil at small, moderate, and large angles of attack [10].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation and experiments on turbulent air flow around the semi-circular profile at zero angle of attack and moderate Reynolds number

et al. 2019

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Two-dimensional flow around a semi-circular profile at the zero angle of attack and at Re = 50000 on the self-oscillatory period is extensively studied by the URANS method involving the standard semi-empirical SST turbulence models, the SST turbulence model with the correction for streamline curvature modified within the Rodi-Leschziner-Isaev and Smirnov-Menter approaches, as well as involving Hanjalic's four-parameter eddy viscosity elliptic relaxation model and its analog-eddy viscosity elliptic blending model proposed in the present work. This has been done with the use of different-structure grids (multiblock with structured overlapping and unstructured composite). Different numerical approximation methods realized in six codes (VP2/3, SigmaFlow, Fluent, CFX, OpenFOAM, and StarCCM+) are used. An underestimation (up to 30%) of time-averaged integral aerodynamic loads is revealed by means of the standard near-wall SST model. This is explained by the high vortex viscosity production in the profile wake. Wind tunnel tests show that the location of cutoff washers on the semi-circular profile provides a quasi-two-dimensional flow around it and allows applying measurement data to verify two-dimensional turbulent flow. The best agreement of experimental results and numerical predictions when comparing the Strouhal number and time-averaged surface pressure coefficient distributions is achieved using both the modified SST model with the correction for streamline curvature and the modified eddy viscosity elliptic blending model. When the SST model with the correction for streamline curvature, modified within the Rodi-Leschziner-Isaev, Smirnov-Menter and Durbin approaches, is used, all the above codes yield close predictions of a vertical aerodynamic load on the oscillation period.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation and experiments on turbulent air flow around the semi-circular profile at zero angle of attack and moderate Reynolds number

et al. 2019

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“…A comparison of this airfoil with the ECAP airfoil has shown that, at moderate angles of attack of the order of 10 o , the traditional airfoil has a somewhat larger (by 32-35%) lift at the same values of the lift-drag ratio and the coeffi cient C x . In [9], different methods of suction of air from the vortex cells positioned on an ECAP airfoil: the distributed suction of air from the surface of the central bodies and the concentrated (slot) suction, were compared. It was established that, at moderate Mach numbers of the order of 0.4, the lift-drag ratio of the ECAP airfoil with slot suction is more than fi ve times larger than that in the case of distributed suction.…”

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Optimization of the Slot Suction of Air from a Circular Vortex Cell on a Thick NACA0022 Airfoil with a Maximum Lift–Drag Ratio

Исаев

Kalinin

Sudakov

et al. 2015

J Eng Phys Thermophy

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On the basis of multiblock computational technologies and the Menter model of shear-stress transfer modifi ed with account of the curvature of streamlines, the optimum position of a slot for air suction on the leeward side of the contour of a vortex cell built in a thick NACA0022 airfoil was determined for the purpose of increasing its lift-drag ratio to a maximum value in a nondisturbed air fl ow at a Mach number of 0.05 and an angle of attack of 7 o .Interest in the aeromechanics of thick airfoils with vortex cells is in many respects due to the need for the design of promising fl ying vehicles, such as the ECAP (ecology and progress) fl ying vehicle with an integral arrangement comprising a fuselage and carrying surfaces [1]. In [2][3][4][5][6][7][8], control of the fl ow around a thick airfoil of thickness 37% (in fractions of the chord) with a contour consisting of circular arcs connected by a straight-line segment from below, providing a large lift-drag ratio and a large light coeffi cient of the airfoil, was realized due to the organization of distributed suction of air from the surfaces of the central bodies positioned in the four elliptical vortex cells built in the backside of the airfoil. In these works, results of calculations of the turbulent fl ows of an incompressible fl uid and a compressible gas around an ECAP airfoil, including in the transonic regime at angles of attack and Reynolds and Mach numbers changing in wide ranges, are presented. In the determination of the aerodynamic characteristics of this airfoil, the energy expended for the suction of air from a vortex cell was taken into account by introduction of the additional resistance C xa related to the power necessary for the removal of air from the cell on the assumption that it outfl ows to the region with a zero pressure [3]. The coeffi cient C q , defi ning the rate of distributed suction of air from the vortex cells, was selected so that the overall-drag coeffi cient C x is minimum and the coeffi cients C y and K are maximum for the fl ow regime with self-similar Reynolds numbers larger than 10 5 . The critical Mach numbers (of the order of 0.45), at which vortex cells cannot work, were determined. In [8], the fl ow of an incompressible fl uid around a thick Göttingen airfoil was analyzed. A comparison of this airfoil with the ECAP airfoil has shown that, at moderate angles of attack of the order of 10 o , the traditional airfoil has a somewhat larger (by 32-35%) lift at the same values of the lift-drag ratio and the coeffi cient C x . In [9], different methods of suction of air from the vortex cells positioned on an ECAP airfoil: the distributed suction of air from the surface of the central bodies and the concentrated (slot) suction, were compared. It was established that, at moderate Mach numbers of the order of 0.4, the lift-drag ratio of the ECAP airfoil with slot suction is more than fi ve times larger than that in the case of distributed suction. In [10], it was proposed to widen the range of Mach numbers to 0.6 for the MQT air...

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Verification of the Shear-Stress Transfer Model and its Modifications in the Calculation of a Turbulent Flow Around a Semicircular Airfoil with a Zero Angle of Attack

Исаев

Baranov

Zhukova

et al. 2016

J Eng Phys Thermophy

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Modeling the increase in aerodynamic efficiency for a thick (37.5% chord) airfoil with slot suction in vortex cells with allowance for the compressibility effect

Cited by 10 publications

References 5 publications

Numerical simulation and experiments on turbulent air flow around the semi-circular profile at zero angle of attack and moderate Reynolds number

Numerical simulation and experiments on turbulent air flow around the semi-circular profile at zero angle of attack and moderate Reynolds number

Optimization of the Slot Suction of Air from a Circular Vortex Cell on a Thick NACA0022 Airfoil with a Maximum Lift–Drag Ratio

Verification of the Shear-Stress Transfer Model and its Modifications in the Calculation of a Turbulent Flow Around a Semicircular Airfoil with a Zero Angle of Attack

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