Improvement of the cruise performances of a wing by means of aerodynamic optimization. Validation with a Far-Field method

Abstract

Under a contract with AIRBUS MILITARY (AI-M), an exercise to analyze the potential of optimization techniques to improve the wing performances at cruise conditions has been carried out by using an in-house design code. The original wing was provided by AI-M and several constraints were posed for the redesign. To maximize the aerodynamic e©ciency at cruise, optimizations were performed using the design techniques developed internally at INTA under a research program (Programa de Termo §uidodin‚ amica). The code is a gradient-based optimization code, which uses classical ¦nite di¨erences approach for gradient computations. Several techniques for search direction computation are implemented for unconstrained and constrained problems. Techniques for geometry modi¦cations are based on di¨erent approaches which include perturbation functions for the thickness and/or mean line distributions and others by B‚ ezier curves ¦tting of certain degree. It is very important to a¨ord a real design which involves several constraints that reduce signi¦cantly the feasible design space. And the assessment of the code is needed in order to check the capabilities and the possible drawbacks. Lessons learnt will help in the development of future enhancements. In addition, the validation of the results was done using also the well-known T AU §ow solver and a far-¦eld drag method in order to determine accurately the improvement in terms of drag counts.

Geometric manipulation of NURBS surfaces for computational meshes

“…Bumps or Hicks-Henne functions These functions [15,66,24] actuate directly on the surface like a cubic sinus bump. They became popular by its simplicity and the possibility to apply several of them to model small or moderate perturbations of an initial geometry shape.…”