Document Type

Article

Journal/Book Title/Conference

Applied Sciences

Author ORCID Identifier

Amanda K. Olsen https://orcid.org/0009-0006-5122-3206

Douglas F. Hunsaker https://orcid.org/0000-0001-8106-7466

Volume

15

Issue

17

Publisher

MDPI AG

Publication Date

8-30-2025

Journal Article Version

Version of Record

First Page

1

Last Page

20

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

When a flying wing comes within close proximity to the ground, a phenomenon called ground effect occurs where the lift is increased and the induced drag is decreased. This research seeks to determine the optimal dihedral distribution predicted by lifting-line theory that minimizes induced drag in ground effect. Despite some limitations, using lifting-line theory for this study allows for quick results across a large range of design variables, which would be infeasible for high-fidelity methods. The SLSQP optimization method is used along with a numerical lifting-line code to find the dihedral distribution that minimizes induced drag. Results are presented showing how the wing height, taper ratio, lift coefficient, and aspect ratio impact the induced drag and optimal dihedral distributions. For a given geometry, lifting-line theory predicts that there is a certain height above ground where the optimal solutions for a wing below this height result in bell-shaped wings with large section dihedral angles corresponding to a significant induced-drag reduction. For example, a wing with 𝑅𝐴 = 8 and height of β„Ž/𝑏 = 0.25 can benefit from a reduction in induced drag of nearly 50% by employing an optimal dihedral distribution compared to a wing with no dihedral distribution.

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