Experimental study on flow kinematics and pressure distribution of green water on a rectangular structure

Abstract

In this study, flow kinematics and pressure distribution of green water on a fixed rectangular structure were investigated with a series of experiments performed in a two-dimensional wave flume. The experiments were conducted under regular wave conditions which were scaled down by a ratio of 1:125 from the BW Pioneer Floating Production Storage and Offloading (FPSO) operated in the Gulf of Mexico. PIV and BIV measurements were applied to obtain the water and bubbly flow in order to study the flow kinematics of multi-phase flow induced by green water. The mass flow rate and the kinetic energy, which were calculated from the water velocity profiles obtained by the PIV measurements were compared with and without the structure to investigate the quantitative flow kinematics of the water flow at the weather side of the structure. The characteristics of the bubbly flow in the water shipping phase on the deck were investigated based on the velocities of the bubbly flow obtained by the BIV measurements, and the velocities of the bubbly flow were compared with the solutions of dam break theory. Pressure measurements were taken along the structure to estimate the local loading of the green water phenomena and they provided the maximum peak pressure, rise time, impulsiveness of the pressures, and the peak frequencies of the pressure oscillation due to the air pocket generation on the wall of the structure during the green water.