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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...
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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