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A Mesh-Based Approach for Computational Fluid Dynamics-Free Aerodynamic Optimisation of Complex Geometries Using Area Ruling

Ben Evans Orcid Logo, Ben Smith, Sean Walton Orcid Logo, Neil Taylor, Martin Dodds, Vladeta Zmijanovic

Aerospace, Volume: 11, Issue: 4, Start page: 298

Swansea University Authors: Ben Evans Orcid Logo, Sean Walton Orcid Logo

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Abstract

In this paper, an optimisation procedure is introduced that uses a significantly cheaper, and CFD-free, objective function for aerodynamic optimisation than conventional CFD-driven approaches. Despite the reduced computational cost, we show that this approach can still drive the optimisation scheme...

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Published in: Aerospace
ISSN: 2226-4310
Published: MDPI AG 2024
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa70872
Abstract: In this paper, an optimisation procedure is introduced that uses a significantly cheaper, and CFD-free, objective function for aerodynamic optimisation than conventional CFD-driven approaches. Despite the reduced computational cost, we show that this approach can still drive the optimisation scheme towards a design with a similar reduction in drag coefficient for wave drag-dominated problems. The approach used is ‘CFD-free’, i.e., it does not require any computational aerodynamic analysis. It can be applied to geometries discretised using meshes more conventionally used for ‘standard’ CFD-based optimisation approaches. The approach outlined in this paper makes use of the transonic area rule and its supersonic extension, exploiting a mesh-based parameterisation and mesh morphing methodology. The paper addresses the following question: ‘To what extent can an optimiser perform (wave) drag minimisation if using ‘area ruling’ alone as the objective (fitness) function measurement?’. A summary of the wave drag approximation in transonic and supersonic regimes is outlined along with the methodology for exploiting this theory on a typical CFD surface mesh to construct an objective function evaluation for a given geometry. The implementation is presented including notes on the considerations required to ensure stability, and error minimisation, of the numerical scheme. The paper concludes with the results from a number of (simple and complex geometry) examples of a drag-minimisation optimisation study and the results are compared with an approach using full-fidelity CFD simulation. The overall conclusions from this study suggest that the approach presented is capable of driving a geometry towards a similar shape to when using full-fidelity CFD at a significantly lower computational cost. However, it cannot account for any constraints, driven by other aerodynamic factors, that might be present within the problem.
Keywords: evolutionary optimisation; area ruling; wave drag; Sears–Haack
College: Faculty of Science and Engineering
Funders: The authors would like to acknowledge the support provided by Reaction Engines Ltd. and EPSRC under grant number EP/T517987/1 for provision of funding to support this work.
Issue: 4
Start Page: 298