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The paper presents a numerical framework for the aerodynamic analysis of aircraft wings in transonic cruise and take-off/landing compatible with preliminary and conceptual design phase requirements based on the Non-Linear Vortex Lattice Method (NL-VLM). The purpose of this work is to demonstrate the applicability of the VLM-2.5D RANS approach for aircraft design optimization. The algorithm captures wing sweep effects, important in the transonic regime and near C Lmax conditions, by a stripwise viscous-inviscid coupling strategy with an infinite-swept wing (2.5D) Reynolds-Averaged Navier-Stokes (RANS) solver. Aerodynamic forces are evaluated through spanwise integration of the 2.5D RANS solutions and a trefftz-plane analysis of the VLM solver. The framework allows calculations of single and multi-element configurations without modifying the VLM mesh. A novel C Lmax criteria is proposed based on recently observed stall-cells patterns that captures C Lmax , α max and the spanwise location of the stall, which represent important design parameters. The applicability of the framework to aircraft design is demonstrated by embedding the analysis tools into a gradient-free Covariance Matrix Adaptation Evolution Strategy. After a verification phase, validation is performed on high-speed, high-lift and combined high-speed/high-lift optimisations cases. In particular, the capability of the numerical algorithms towards multi-topology optimisation is demonstrated.

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