Open Access

ARTICLE

Heave-Induced Thrust and Free-Surface Deformation of an Oscillating Hydrofoil

Feiyang Liu¹, Yi Zhou¹, Decai Qu², Bowen Zhao^3,*

1 Department of Hydroaeromechanics and Marine Acoustics, Saint-Petersburg State Marine Technical University, Saint-Petersburg, Russia
2 College of Engineering, Ocean University of China, Qingdao, China
3 Department of Applied Mathematics and Mathematical Modeling, Saint-Petersburg State Marine Technical University, Saint-Petersburg, Russia

* Corresponding Author: Bowen Zhao. Email:

Fluid Dynamics & Materials Processing 2026, 22(9), 10 https://doi.org/10.32604/fdmp.2026.087716

Received 22 June 2026; Accepted 15 September 2026; Issue published 28 September 2026

Abstract

The effects of heave amplitude and oscillation period on the hydrodynamic performance of a three-dimensional NACA0012 hydrofoil operating beneath a free surface are systematically investigated using an unsteady Reynolds-averaged Navier–Stokes (RANS) framework coupled with the Volume of Fluid (VOF) method. The shear stress transport (SST) turbulence model and an overset mesh technique are employed to resolve the turbulent flow and large-amplitude hydrofoil motion, while grid and time-step convergence studies are performed to establish numerical reliability. The results show that the heaving hydrofoil generates net thrust throughout the investigated parameter range, demonstrating the dominant role of the motion-induced effective angle of attack in determining the streamwise force. Increasing the oscillation frequency generally enhances thrust production by strengthening momentum exchange within the wake. Heave amplitude has a pronounced influence on the surface pressure distribution, with larger amplitudes intensifying the leading-edge suction peak, increasing the pressure difference between the upper and lower surfaces, and consequently amplifying the instantaneous hydrodynamic loads. Concurrently, both free-surface wave elevation and wake vorticity increase with heave amplitude, indicating increasingly strong interactions between the vortical wake and the free surface. At excessive amplitudes, however, a greater fraction of the input energy is transferred to surface-wave deformation and vortical structures rather than converted into useful thrust.

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Keywords

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