不同吃水条件下船舶运动及附加阻力的研究

Study of ship motion and additional resistance at different drafts

为研究不同吃水对船舶运动与附加阻力的影响,本文基于计算流体动力学建立了满载、压载以及满载和压载之间2个吃水条件下KVLCC2船舶数值模型。利用Fluent软件和势流理论计算得到不同吃水船舶在波浪中升沉、纵摇运动响应和附加阻力值,并与实验结果对比分析。研究表明:计算流体力学数值模拟船舶运动与附加阻力具有较高的准确性;船舶升沉运动受吃水条件影响大于纵摇运动;针对不同吃水条件,提出吃水形状因子改进附加阻力半经验公式。

To determine the influence of different drafts on ship movement and additional resistance,KVLCC2 ship numerical models are established based on computational fluid dynamics(CFD).Four draft conditions are employed namely:full load,ballast,and two intermediate conditions between the full load and ballast conditions.The heave,pitch motion response,and additional resistance values of ships with different drafts in waves are calculated through potential flow theory and using Fluent software.Data acquired are then compared and analyzed with the experimental results.Results reveal high accuracy achieved from the numerical simulation of the ship motion and additional drag incorporated through CFD.Meanwhile,the heave motion of a ship is more affected by draft than the pitching motion.Finally,an improved semi-empirical formula of draft shape factor is proposed according to different draft conditions.