Multi-Point Aerodynamic Shape Optimization of Angular Airfoils for Micro-Scale Mars Airplane
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The authors have conducted aerodynamic shape optimization of angular airfoils for a micro-scale Mars airplane under the near-surface Martian flight condition (Reynolds number of 1.0 × 10⁴ and Mach number of 0.6) [1]. The optimized airfoils exhibited increased lift coefficients, reduced drag coefficients, and improved lift-to-drag ratios compared with triangular airfoil. A total of 151 non-dominated (Pareto-optimal) airfoils were obtained, all of which shared a concave geometry on the upper surface near the leading edge. This geometric feature was found to generate a strong low-pressure region accompanied by localized flow recirculation, resulting in enhanced lift and reduced aerodynamic drag (Figs 1 and 2). These results demonstrated that angular airfoils with appropriately designed concave leading-edge geometries are promising candidates for efficient and structurally feasible wings for future micro-scale Mars airplanes. However, the previous study focused solely on single cruise flight condition and did not consider pull-up conditions associated with higher Mach numbers (M = 0.9), which are critical for maneuvering and flight safety. Under such conditions, increased lift demand and stronger compressibility effects can lead to aerodynamic characteristics that are significantly different from those at cruise. In this study, multipoint aerodynamic optimization is performed to simultaneously consider both cruise condition at M = 0.6 and pull-up flight condition at M = 0.9. The objectives of the optimization problem are maximization of the lift-to-drag ratio under cruise condition and maximization of the lift coefficient under pull-up condition. Constraints are applied to minimum airfoil thickness, cross-sectional area, and pitching moment. The airfoil geometry is parameterized using multiple straight-line segments, resulting in an angular airfoil defined by 11 design variables. Aerodynamic performance is evaluated using two-dimensional compressible Navier–Stokes simulations. A multiobjective evolutionary algorithm, CHEETAH/R, is employed for optimization. In the oral presentation, the results of the multi-point aerodynamic design optimization of angular airfoil for the micro-scale Mars airplane will be presented.
