Objectives During side-by-side operations of two floating bodies, due to their close proximity, significant wave oscillations within the gap and large-amplitude motion responses of the floating bodies can easily occur under hydrodynamic interactions, posing serious threats to operational safety. Therefore, this study investigates the hydrodynamic interference characteristics between two floating bodies of different principal dimensions.

Methods A hybrid two-way coupled field-domain decomposition method was employed to establish a numerical wave tank, combined with the overset technology to simulate the motion characteristics of the two floating bodies. The hydrodynamic interference between two floating bodies of different dimensions in regular waves was studied. Firstly, the hydrodynamic resonance phenomenon in the gap between two floating bodies of the same principal dimensions was numerically simulated and compared with experimental data to validate the accuracy of the numerical model. Subsequently, the heave motion of two floating bodies of different dimensions in regular waves was simulated, and the effects of different floating body arrangements on their vertical motion responses were analyzed.

Results The results indicate that, compared to the CFD method, the hybrid two-way coupled field-domain decomposition method offers higher computational efficiency while ensuring accuracy when validated against experimental data. Under high-frequency conditions, the two floating bodies tend to exhibit anti-phase motion. Additionally, when the larger floating body is positioned upstream, it demonstrates a significant shielding effect on the downstream smaller floating body.

Conclusions This study employs the hybrid two-way coupled field-domain decomposition method to validate the accuracy of the hydrodynamic interference model between two floating bodies. It reveals the anti-phase motion of the two floating bodies under high-frequency conditions and the shielding effect when the larger floating body is upstream, providing theoretical support for optimizing floating body arrangements and enhancing operational safety.