Research on the Stability of the Ballast Water Tank on the Offshore Floating Platform Based on Numerical Simulation

Abstract

The study of stabilisation performance is a crucial consideration in the design of offshore floating platforms. For large floating structures, incorporating passive anti-roll tanks is a common technique for roll reduction. To investigate the feasibility of using ballast tanks for roll attenuation on the Guohaishi-1 platform, this study employs the AQWA internal tank theory to analyze the influence of four independent empty tanks, located around the platform, acting as anti-roll tanks with varying ballast water volumes. The results indicate that: (1) Different ballast water volumes within a single tank do not significantly affect the static stability parameters of the platform. (2) In regular wave simulations, the ballast tanks show limited effectiveness in reducing roll motion along the wave incidence direction but effectively suppress coupled responses in other degrees of freedom. (3) In irregular wave simulations, the ballast tanks effectively reduce the heave amplitude of the platform, thereby enhancing its wave-following performance in the heave degree of freedom. (4) A CNN_BiLSTM_Attention algorithm is developed using AQWA generated datasets to predict the pitch motion time series of the platform under different ballast water conditions and sea states, while the model has a superior prediction performance. Future work will further explore the application of ballast tanks on floating platforms, optimize their performance, and develop appropriate neural network models to predict motion responses under different ballast configurations. Additionally, efforts will be made to establish suitable evaluation metrics for assessing the effectiveness of ballast tank designs.

Keywords: marine platforms, stability performance, anti-roll tank, hydrodynamic analysis, deep learning neural networks