Abstract

This paper focuses on an innovative modeling approach of a floating body in a continuous wave current. This approach is Lagrange-based providing finite particles, which represent discrete hydrodynamic properties in contrast to continuous hydrodynamics. It is implemented into a computationally efficient numerical multi-body simulation program, which is flexible in geometry and dynamic load spectrum. It features a particle-based liquid model and provides time accurate hydrodynamic pressure results in three dimensions and 6 Degrees-of- Freedom. Based on the results of dam break tests and sloshing analysis, unsteady impact loads are computed for a floating body in a closed-loop simulation. The wave current is modeled as a continuous flux of particles with velocity-based boundary conditions at the inlet and outlet. Thereby, the floating body geometry is flexible in terms of wall friction, elasticity laws and damping coefficients. A special focus is set on the wave interaction characteristics and the resulting acceleration of the floating body due to the hydrodynamic forces.

Introduction

Dynamic loading of floating bodies is one of the key issues for an improved efficiency in offshore installations and ship operations. Especially the understanding of the hydrodynamic load distribution over the floating body surface in a wave current and the peak pressures during that interaction are of importance. A scientific approach to the floating body dynamics consists of a step-by-step analysis of the physical phenomena involved. First, the flow pattern around a fixed reference body needs to be understood before a floating body is envisaged. In addition to that, in that early step a submerged body undergoing pure hydrodynamic forces is considered, which does not consider buoyancy effects of the real floating body. For that case Arnold et al. (2015) have proposed an experimental setup to analyze submerged body dynamics with the help of a submerged pendulum.

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