Aerodynamic Issues in MDO for Preliminary Design of an Innovative Configuration

The algorithms used by the authors in their MDO‐PD (Multi‐Disciplinary Optimization ‐ Preliminary Design) code for aerodynamics modeling are reviewed. For the aerodynamic analysis, a boundary‐element potential‐flow method is used. Also, the authors review some recent developments aimed at extending, to viscous and compressible flows around innovative configurations, the aerodynamic modeling used in the code, currently limited to incompressible potential flows. The methodology is geared specifically towards MDO‐ PD for civilian aircraft. Accordingly, the viscous‐flow is limited to the case of attached high‐Reynolds‐ number flows, and the traditional potential‐viscous interaction technique is utilized to take into account the effects of viscosity. An integral boundary layer approach is used for the viscous‐flow analysis. The Lighthill transpiration velocity is used for coupling. Validating comparisons with available ‐ numerical and experimental ‐ results are included. The numerical formulation is applied to a specific, highly‐innovative aircraft configuration proposed by A. Frediani, which has, as a distinguishing feature, a low induced drag.