Prediction of waves in tanks excited by ship motion and moving walls with a three-dimensional fully linear finite difference approach

Mitigation of waves in shipboard swimming pools excited by ship motions is a topic of current interest that has not yet been extensively investigated. Various damping mechanisms have been applied to mitigate waves excited in tanks, such as porous baffles or different types of internal baffles. However, most of these devices are installed in LNG tanks to prevent serious sloshing effects. Furthermore, these are passive devices and, hence, unable to control wave-induced excitations. Our focus was on the validation and verification of the three-dimensional (3D) fully linear Finite Difference Method (FDM) based on the previously developed method of Qi et al. (2024) for predicting waves in a transversely placed swimming pool excited by ship motions and piston-type actuators. We validated our FDM approach against comparative Computational Fluid Dynamics (CFD) simulations as well as experimental model test measurements. The CFD tools solved the Reynolds-averaged Navier-Stokes (RANS) equations, relied on an appropriate turbulence model and the Volume of Fluid (VOF) method to capture the free surface of the liquid in the model tank, and employed the overset technique to specify the motions of the active actuators. Our FDM considered ship-induced roll excitations as well as simultaneous roll and sway excitations, albeit only at frequencies outside the range of the pool's resonance frequency. For these periods, our approach accurately predicted not only the mitigated waves in the pool, but also the optimum amplitude of the actuators needed to mitigate such waves. Our FDM can be applied to obtain a preview of excited waves under various conditions, leveraging its principal advantage of extreme computational efficiency.

Subjects

Finite difference method

Frequency domain

Model test

Navier-Stokes equations

Overset technique

Sloshing

Volume-of-fluid method

Wave damping

DDC Class

620: Engineering

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by-nc/4.0/

Name

1-s2.0-S0029801824019863-main.pdf

Type

Main Article

Size

12.28 MB

Format

Adobe PDF

Options

Prediction of waves in tanks excited by ship motion and moving walls with a three-dimensional fully linear finite difference approach