Year: 2025
Type: article
Abstract: The flow dynamics and performance of tandem foils, both with and without ground effect (GE), continue to present challenges that are critical to understanding and optimizing aero/hydrodynamic systems, particularly for applications in next-generation wing-in-ground (WIG) effect vehicles, sailing yachts, and hydrofoil vessels.The performance of foils in GE (IGE) versus out of GE has not been extensively compared.This comprehensive study investigates the aero/hydrodynamic performance and flow dynamics of tandem foils using NACA 4412 section at moderate Reynolds number.To isolate the effects of spacing and ground clearance (H), both foils were set at a fixed angels of attack to negate the influence of decalage angle.The design variables examined include horizontal and vertical spacing between the foils, as well as H. Performance comparisons in both GE and out-of-GE conditions were presented, focusing on lift-to-drag ratio, lift and drag, and foil-to-foil interaction dynamics.Numerical simulations were conducted using the finite-volume method to solve the incompressible Reynolds-averaged-Navier-Stokes equations with the shear-stress transport k-ω turbulence model with gamma-transition model.Results indicate that the superiority of tandem foils is highly configuration-dependent. IGE, tandem foils exhibit a significantly higher lift-to-drag ratio than in out-of-GE conditions, where their performance is often lower than that of isolated foils.Positive G between the foils were found to enhance aero/hydrodynamic efficiency, suggesting that optimizing the gap distance can lead to performance improvements.The stagger distance plays a critical role in altering the static pressure distribution due to foil-to-foil interactions.Notably, under certain interference conditions, the fore foil can experience reduced drag or even generate thrust, offering potential advantages for specific aero/hydrodynamic applications.These findings provide new insights into the behaviour of tandem foils and may inform the design of next-generation WIG vehicles, hydrofoil vessels, tandem sails, and other systems where foil interactions are significant.
Authors: Mehmet Delikan, Şakir Bal
Institution: Istanbul Technical University
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4410105573