RANS-Based Aerodynamic Shape Optimization of a Strut-Braced Wing with Overset Meshes

Abstract

The strut-braced wing aircraft configuration promises to reduce fuel burn by enabling higher spans that reduce lift-induced drag. A successful design for this configuration depends on a careful trade-off between the various sources of drag and structural weight. When using computational fluid dynamic tools for aerodynamic shape optimization, generating high-quality structured meshes for the strut-braced wing configuration becomes challenging, especially near junctions. Furthermore, mesh deformation procedures frequently generate negative volume cells when applied to these structured meshes during optimization. This paper addresses this issue by using overset meshes and a component-based parametrization technique to achieve a flexible design optimization cycle capable of handling changing junctions. This study uses this approach to minimize drag of the PADRI 2017 strut-braced wing benchmark for a fixed lift constraint at transonic flight conditions. The drag of the optimized configuration is 15% lower than the baseline due to the reduction of shocks and separation in the wing-strut junction region. This result represents an example in which high-fidelity modeling is required to quantify the benefits of a new aircraft configuration and address potential issues during the conceptual design.