Flows past airfoils for the low-Reynolds number conditions of flying in Martian atmosphere.

Fixed-wing aircraft with potential for long-duration flight and efficient manoeuvrability is expected to be the next frontier of Mars surface exploration. However, the feasibility of such an aircraft demands for wing airfoil suitable for low Reynolds flight conditions. In this framework, the paper deals with the computational study of two wing sections specifically designed for Mars exploration aircraft. Two-dimensional steady Reynolds-averaged Navier–Stokes simulations, using the computational fluid dynamics tool SU2 with the γ − R e θ transition model and the XFoil panel flow solver, are performed to address airfoils' aerodynamics. Computational tools are validated by simulating flow past the Eppler 387 airfoil at R e ∞ = 60 × 1 0 3 , and comparing the results with experimental data collected in wind tunnel experiments. Aerodynamic performances of optimal wing sections are investigated at R e ∞ = 3. 4 × 1 0 4 by considering pressure coefficients and skin friction coefficients. The application of a literature-based correlation, specifically tailored to identify transition and reattachment locations, is extended to separation point detection. Computational Fluid Dynamics analysis conducted on the studied airfoils revealed that separation occurs within the laminar regime. Additionally, examination of turbulent shear stresses highlighted the role of airfoil curvature in counterbalancing the suction defect produced by the laminar separation bubble. This curvature-induced effect was found to play a crucial role in optimizing airfoil efficiency. • Aerodynamics issues of flying in Martian atmosphere. • Computation of flows past airfoils for future Mars exploration aircraft. • Detection of transition and separation at low-Reynolds number. [ABSTRACT FROM AUTHOR]