Experimental and numerical studies on hydrodynamic effects of ice floe drift and impact process in uniform current

The safety of offshore structures is often threatened by the impact load of isolated ice floes. However, the accurate estimation of the impact load can be challenging due to the unquantified near-field hydrodynamic interaction. In this paper, the hydrodynamic interactions between ice floes and offshore structures are investigated by a model experiment and the numerical calculation. The model experiment is conducted to study the whole process of a model ice drifting and impacting a cylinder under the influence of uniform flow. Meanwhile, the interaction process is also numerically simulated by using the Computational Fluid Dynamics (CFD)-Finite Element Method (FEM) coupling method. The experimental and numerical results show good agreement in terms of velocity time histories, peak impact forces and peak accelerations. The influences of current velocity, ice floe size, and ice floe shape on various interactions are discussed based on numerical results, including the velocity attenuation effect before impact, the added mass effect during collision, the kinetic energy and motion attitude of the ice floe. The main findings of present research suggest that the viscous effect in near-field and the bow wave are noteworthy factors causing the velocity attenuation of the ice floe and ignoring these influences can lead to underestimation of the velocity attenuation effect to some extent. Additionally, the (effective) added mass coefficients calculated based on the ice floe motion equation and the momentum balance equation are found to be close to each other. However, with the decreasing of the ice floe size, the difference between the added mass coefficients calculated by the two methods gradually increases. •The whole process of an ice floe drifting and impacting on a cylinder is conducted.•The shape factors that influence hydrodynamic interactions are captured.•Significant velocity attenuation has been observed for floe size larger than of cylinder.•The calculated added masses during collision based on motion equation and momentum equation are close.