Semi-analytical study on the hydrodynamic performance of a cylindrical moon column FPSO with damping plate

This paper investigates the hydrodynamic performance of a pool-type cylindrical Floating Production Storage and Offloading (FPSO) unit equipped with a bottom damping plate designed to mitigate heave motion. Using a semi-analytical approach, we developed a three-dimensional model based on linear potential flow theory to conduct a comprehensive hydrodynamic analysis of the floating structure. The methodology integrates the eigenfunction matching method with significant nonlinear boundary conditions. We systematically evaluate the wave load and heave motion characteristics of both the entire device and the damping plate, considering various dissipation coefficients and geometric parameters of the damping plate. To validate the accuracy of the proposed semi-analytical model, we compare the results with experimental data and numerical simulations. The calculated results reveal a strong positive correlation between wave loads and different damping plate geometries, with subtle variations in specific directions within the high-frequency domain. Incorporating dissipation coefficients into the potential calculation significantly mitigates abrupt fluctuations in hydrodynamic coefficients at resonant frequencies, enhancing the stability and reliability of the computational results. Additionally, optimizing the geometric parameters of the damping plate substantially influences the hydrodynamic coefficients, particularly for the heave motion of the device. The forces acting on the damping plate under various conditions in irregular incident waves underscore the critical impact of the damping plate on structural safety. The findings identify an optimal damping plate design for a pool-type FPSO to enhance anti-heave effectiveness, providing valuable insights for engineering design.