Goyang/Seoul, June 2025

Jan Modderman* ([email protected]), Oriol Colomés* ([email protected])

Abstract

In the design and analysis of offshore structures, accurate estimation of hydrodynamic coefficients is critical to predicting forces, moments, and dynamic responses under complex marine conditions. Traditional methods for obtaining these coefficients, such as empirical modeling, scale testing, and fitted mesh-based Finite Element Methods (FEM), face limitations in capturing interactions with intricate or evolving geometries characteristic of offshore structures. This paper presents a novel approach leveraging an unfitted FEM [1] for the estimation of hydrodynamic coefficients in complex offshore environments. Unlike conventional FEM that requires a mesh conforming to structural boundaries, the unfitted approach allows for an independent, background mesh that does not need to align with the structure’s geometry. This flexibility enables efficient handling of complex geometries and free-surface interactions, reducing preprocessing time and computational cost while maintaining high accuracy. We validate the method against both benchmark cases and traditional empirical models, demonstrating improved accuracy and robustness. Application to various offshore structures, including floating platforms and wind turbine foundations, underscores the method’s capability to accurately capture essential hydrodynamic coefficients, such as added mass, and damping, under realistic marine conditions. This unfitted FEM approach offers a scalable and adaptable tool for hydrodynamic analysis, providing significant advantages in efficiency over models traditionally used in offshore structural design and performance prediction.

Brief Presentation

Aim:

Verification of the estimation of hydrodynamic coefficients of offshore structures with complex geometries

Proposed Approach:

Aggregated unfitted Finite Element Method

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