ASSESSMENT OF SHIP KINEMATICS AND LIQUID CARGO DYNAMICS DUE TO ICE COLLISION

摘要

The development and transportation of hydrocarbons in Arctic region demands on the cutting-edge vessels enable shipping in severe ice conditions without icebreaking assistance. However independent navigation in ice-infested waters put new challenges for liquid cargo vessels, such as: LNG carriers (LNGC) and oil tankers. Ramming or unexpected collision with multi-year ice and stamukhas can slow down or stop the ship suddenly, resulting in violent sloshing of liquid cargoes, especially LNG. This study describes an algorithm which first predicts ship kinematics due to glancing impact and ship's jamming in ice to assess the accelerations and velocities for the 6 degrees of freedom (DOF). Second, these accelerations time histories are used in order to perform computational fluid dynamics (CFD) calculations to predict liquid motion inside the LNG tanks and the subsequent sloshing loads. Finally, the obtained sloshing loads are used for the sloshing assessment. Operability of the presented algorithm is demonstrated through some application to a 170000 m~3 LNGC sailing in ice. The algorithm includes solution of theoretical mechanics problem of two bodies' impact, ship and ice motions, ice failure mechanics, LNG motion inside the tanks and sloshing effects of LNG.