Numerical Simulation of Single Ice Floe Motion Response under Actions of Wind,Wave and Current
With global warming,the number of ice floes increases in the marginal ice zone(MIZ),which may create threats to the marine structures in polar regions.In order to predict the response characteristics of ice floes under environmental loads in MIZ,the motion responses of a single ice floe in wind drag condition,current drag condition,wind-wave combined condition and current-wave combined condition are simulated respectively.For the former two conditions,under the drag of wind or current alone,the drift of the ice floe presents two stages:the initial accelerating stage and the stable balanced stage.During the initial accelerating stage,there is a low-pressure zone on the upstream side of the ice floe,and coupled movement characteristics between the heave motion and pitch motion arise.For the latter two conditions,a linear method using the superposition of drift velocities caused by pure wave and by drag force is adopted to estimate the ice floe drift velocity.This linear estimation method generally conforms well to the simulation results when the wind speed is less than 7 m/s or the current speed is less than 0.08 m/s.In addition,the ice floe motion responses in three degrees of freedom(surge,pitch and heave)are analyzed,in the wind-wave and current-wave combined conditions respectively.The encounter period between wave and the ice floe is estimated based on the ice floe drift velocity,and the results are in good agreement with the motion periods in various degrees of freedom in conditions with relatively low wind or current speed obtained from the numerical simulation.
万方数据
维普
