Parametric excitation of moored wave energy converters using viscous and non-viscous CFD simulations
Book chapter, 2019

The paper discusses the use of CFD simulations to analyse the parametric excitation of moored, full scale wave energy converters in six degrees of freedom. We present results of VOFRANS and VOF-Euler simulations in Open FOAM® for two body shapes: (i) a truncated cylinder; and (ii) a cylinder with a smooth hemispherical bottom. Flow characteristics show large differences in smoothness of flow between the hull shapes, where the smoother shape results in a larger heave response. However the increased amplitude makes it unstable and parametric pitch excitation occurs with amplitudes up to 30°. The responses in surge, heave and pitch (including the transition to parametric motion) are found to be insensitive to the viscous effects. This is notable as the converters are working in resonance. The effect of viscous damping was visible in the roll motion, where the RANS simulations showed a smaller roll. However, the roll motion was found to be triggered not by wave-body interaction with the incident wave, but by reflections from the side walls. This highlights the importance of controlling the reflections in numerical wave tanks for simulations with WEC motion in six degrees of freedom.

Author

Johannes Palm

Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology

Lars Bergdahl

Chalmers, Architecture and Civil Engineering, Water Environment Technology

Claes Eskilsson

RISE Research Institutes of Sweden

Aalborg University

Proceedings in Marine Technology and Ocean Engineering

2638647X (ISSN) 26386461 (eISSN)

Vol. 2025 455-462

Subject Categories (SSIF 2025)

Fluid Mechanics

Marine Engineering

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Latest update

2/13/2025