FUSELAGE SHAPE OPTIMIZATION AIMED AT WING-FUSELAGE CONFIGURATION DRAG REDUCTION AT SUPERSONIC SPEEDS

The problem of fuselage shape optimization of the wing-body configuration is considered in the following three formulations. In the first one, the angle of attack is fixed and equal to zero, the wing has a symmetric airfoil, and the fuselage is based on circular cross sections. In the second one, the fuselage cross sections are elliptical. In the third one, the angle of attack is varied, the lifting force coefficient is fixed, the wing is preliminary optimized, the fuselage is designed by the cross sections that consist of upper and lower half-ellipses with a possibility of a shift along vertical axis. The configuration volume, fuselage length, shape and position of the wing are fixed. The drag coefficient is the objective function. The optimization is carried out by the Indirect Optimization based on Self-Organization (IOSO) technology. Aerodynamic coef- ficients are obtained from the solution of the RANS equations with SST turbulence model by the ANSYS CFX software on the structured multiblock meshes. The results obtained by the optimization are compared with the configuration that is designed by traditional means. The fuselage of this configuration has a cylindrical part in the area of the wing-fuselage connection and nose part of the von Karman’s ogive shape. The solution of the optimization problem in the first formulation reduces drag coefficient at zero angle of attack by approximately 3 %. The use of the fuselage with elliptical cross sections makes it possible to reduce drag coefficient at zero angle of attack by 9 %. The solution of the optimization problem in first two formulations reduces drag coefficient at the wide range of angles of attack. When the lifting coefficient is selected for the third problem formulation as constraint the drag reduction is about 7 %. Additional drag reduction of about 2,5 % is obtained by the use of the fuselage asymmetric relative to the horizontal plane. The optimal fuselage design has a specific grotto in the lower part of the fuselage - the constriction from the sides with continuing height growth. The nose part of the optimal fuselage is widened, has a triangular shape in the top view and is deflected down.

аэродинамическое сопротивление, сверхзвуковые скорости, самолет, оптимизация, фюзеляж, уравнения Рейнольдса, вычислительная аэродинамика

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