Experimental investigation on hydrodynamic performance of submerged floating tunnel under the protection of a new floating energy dissipation and anti-vibration device

This study describes an efficient and applicable approach to decrease the hydrodynamic response of a submerged floating tunnel (SFT). A new type of floating energy dissipation and anti-vibration device is proposed, mainly consisting of a floating box superstructure with water and a polyvinyl chloride porous media substructure. The experimental model of an SFT with the present protection device is designed and conducted in a wave–current flume. The wave–current attenuation mechanisms for the present protection device are experimentally investigated. The sensitivity analysis for the key parameters, e.g., structure type and wave–current parameter, is conducted to investigate the hydrodynamic performance of the SFT with the present protection device. The results show that the present protection device has excellent wave–current attenuation capacity, and the transmission coefficients and the current–velocity attenuation coefficient reach 0.2 and 0.15, respectively. The sway, heave, roll, and typical cable tension from the SFT with the protection are, respectively, about 8, 6, 8, and 3 times smaller than that from without the protection. The results show that the SFT with the present protection device has excellent anti-vibration performance, which is beneficial for its safety and stability. This study has important theoretical and practical values to the anti-vibration design of SFTs serviced in complicated ocean environments.