Effects of gap entrance configuration on gap resonances between two free-heaving barges: Vortex shedding behaviors

Abstract

This paper mainly concentrates on the influences of the vortex shedding pattern and the behaviors of the generated vortex bubbles on the hydrodynamic performances of two identical side-by-side barges when encountering the linear and nonlinear gap resonances. The vortex shedding pattern around the entrance of the gap is highly influenced by the gap entrance configuration, and thus, two kinds of gap entrance configurations, i.e., round edge and square edge, are taken into account. The vortex shedding patterns are identified during the linear and nonlinear gap resonances for all conditions. Meanwhile, the effects of incident-wave height and barges' heave responses are considered when interacting with different edge shapes. Numerical results demonstrated that both the gap resonances and barges' heave responses are influenced by the vortex generation pattern. Significantly, the magnitudes of the wave elevation at gap during the linear and nonlinear gap resonances are influenced by the coupling effect between the vortex bubbles' pre-behaviors, i.e., vortex shedding pattern, and their post-behaviors, i.e., vortex bubbles' behaviors post-shedding from shear layers, underscoring the importance of understanding vortex shedding patterns and the behaviors of vortex bubble in investigating the gap resonances.