Aerodynamic Shape Optimization of a Box-Wing Regional Aircraft Based on the Reynolds-Averaged Navier-Stokes Equations

Abstract

The box wing is an unconventional aircraft configuration that has the potential to provide major savings in fuel consumption relative to the conventional cantilever wing. In order to further develop and evaluate this potential, high-fidelity aerodynamic shape optimization is applied to the aerodynamic design of a box wing and a cantilever wing, based on the Embraer E190 regional jet, with the latter serving as a performance baseline. The optimization framework consists of B-spline parameterization, free-form and axial deformation geometry control, an integrated mesh-movement scheme based on the theory of linear elasticity, a Newton-Krylov-Schur flow solver for the Reynolds-averaged Navier-Stokes equations, a gradient-based optimizer, and the discrete-adjoint method for gradient evaluation. Results indicate that a box-wing with a heightto-span ratio of 0.26 burns 7.61% less fuel at cruise than a conventional baseline of the same span and lift. Aerodynamic trends and trade-offs are investigated, and a weight sensitivity study is performed.ii Acknowledgements First and foremost, I would like to thank my supervisor, Professor David Zingg. I cannot thank him enough for the opportunity to work on such a state-of-the-art problem, which has proven to be challenging, but incredibly rewarding. I also have him to thank for the invaluable knowledge and experience that I have gained during these past few years. His passion for computational aerodynamics and environmentally-friendly aircraft design is something to be envied, and will always serve as a pillar of inspiration. I would also like to thank the UTIAS community for creating a welcoming and fun work environment. To the computational aerodynamics group, thank you for all of the helpful feedback you have given me over the years, and for making my late nights in the lab palatable. In particular, I would like to thank Dr. Shahriar Khosravi for the many interesting discussions on aerodynamics and structures, and Dr. Thomas Reist for his invaluable technical guidance and discussions on aircraft design.

The Interactive Design Approach for Aerodynamic Shape Design Optimisation of the Aegis UAV

“…Due to the fluid nature of the initial design process, it is not recommended to use high fidelity analysis design tools, such as Computational Fluid Dynamics (CFD), at this stage as they can be unnecessarily costly [4,54]. What is required is a tool that strikes a balance between sufficient accuracy and computational cost [55][56][57][58]. Piperni et al [59] and Zhang et al [60] have argued that the level of fidelity that should be delivered by the models is mostly determined at the development stage, which the design process aims to enhance.…”

“…Due to the fluid nature of the initial design process, it is not recommended to use high fidelity analysis design tools, such as Computational Fluid Dynamics (CFD), at this stage as they can be unnecessarily costly [4,54]. What is required is a tool that strikes a balance between sufficient accuracy and computational cost [55][56][57][58].…”

Computational Investigation of a Novel Box-Wing Aircraft Concept

“…In particular, the recent EU project PARSIFAL explored rather extensively the so-called Prandtl Plane concept, which was investigated from various angles, including market perspectives [9], conceptual design viewpoints [10][11][12], and more technical aspects (e.g., performance [13], stability [14], aerodynamics [15,16], structures [17]). Additionally, more specific studies were conducted by several universities, worldwide; several works investigated the BWA concept from design perspectives [20][21][22][23][24][25][26][27] whereas others focused on more specific things such as the aerodynamic efficiency of the box-wing itself [28][29][30][31][32][33][34], as well as structural [35,36] and stability [37][38][39][40] aspects.…”

Artificial Intelligence to Enhance Aerodynamic Shape Optimisation of the Aegis UAV

“…In [43,44], the authors reported developing a strategy that used non-interactive and interactive techniques, respectively, to formulate the design problem and improve the optimisation speed. To deliver a sufficient level of fidelity to the DM at very fast computational times, the low fidelity flow solver Athena Vortex Lattice (AVL) was used to capture the physics of the problem [45][46][47][48]. Improving the ability of the developed method to accelerate the search while retaining all the useful information in the design space was the main area of work.…”

“…The flow solver used to evaluate worthwhile solutions is the Athena Vortex Lattice (AVL) [51,52]. Many codes utilize Vortex Lattice Method (VLM) for aerodynamic characteristics calculations, but AVL is the most well-known and provides the most accurate and efficient results when compared with other aerodynamic analysis software employing the same method [45][46][47][48]52]. In addition, AVL code is easy to use and capable of manipulating a large number of design parameters within a short computational time and limited cost.…”