A New Aspect of the Ground Effect: The Two-way Interactions between an Airplane Flying in the Vicinity of Sea Water and the Free Surface Waves

This study presents intensive numerical simulations of a general aviation airplane flying near a wavy water surface, considering the effects of ground proximity and wave amplitude on aerodynamic forces and moments. The Stokes third-order wave model was employed, and numerical results were validated...

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Bibliographic Details
Main Authors: S. Eftekhari, A. R. Davari, F. Pazooki
Format: Article
Language:English
Published: Isfahan University of Technology 2025-07-01
Series:Journal of Applied Fluid Mechanics
Subjects:
Online Access:https://www.jafmonline.net/article_2708_069b017e354aac16150209aa307a3876.pdf
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Summary:This study presents intensive numerical simulations of a general aviation airplane flying near a wavy water surface, considering the effects of ground proximity and wave amplitude on aerodynamic forces and moments. The Stokes third-order wave model was employed, and numerical results were validated using limited wind tunnel tests on a 3D-printed model, as well as existing NACA 4412 near-ground experimental data. Simulations for both flat and wavy surfaces reveal that above an elevation of h/c=1.5, aerodynamic coefficients remain similar to those near a flat surface. However, at lower clearances, aerodynamic responses exhibit strong oscillatory behavior, potentially leading to resonance and instability. The oscillations in lift (CL​) and drag (CD​) closely follow wave shape, while the pitching moment coefficient (Cm​) shows a distinct phase lag. Large-amplitude waves significantly impact stability, leading to severe pitch oscillations, which may pose risks for aircraft flying near stormy sea surfaces. Contrary to the typically beneficial ground effect for wing-in-ground (WIG) aircraft, this study highlights the destabilizing influence of large surface waves in near-ground flight.
ISSN:1735-3572
1735-3645