Modelling Green Water Impact Load on a Single Circular Cylinder

Abstract

This paper investigates the ability of physical and numerical models to simulate green water impact loads on a circular cylinder located on top of a fixed box. A focused wave group was used to overtop the box and generate the green water event, which resembled a plunging wave with air entrainment. The plunger collapsed and ran across the deck before impacting the cylinder and scattering. With respect to the physical modelling, identical experiments were conducted in two different laboratories, in different countries. The numerical modelling comprised computational fluid dynamics (CFD) simulations performed using OpenFOAM. The flow features, the force on the cylinder and the surface elevation on top of the box are compared in detail across the two physical models and the CFD. Good agreement in the load measurements from the two physical model tests implies very repeatable results despite the complex flow-structure interaction observed. Comparison of the physical and numerical models indicate the flow measured on top of the box and the green water load are sensitive to experimental precision, but agreement is generally satisfactory. This agreement between experiment and CFD serves as an example of the reliability of CFD for modelling green water impact loads.