船舶静水中拖锚淌航距离数值模拟

针对船舶拖锚淌航距离的估算问题,现有方法简单易行,但其计算过程中却忽略船体阻力和附加惯性力对淌航距离产生的影响。忽略这一影响将直接导致所估算的拖锚淌航距离与实际误差较大,不利于航海实践。为此,运用牛顿力学定律描述船舶拖锚淌航过程,以一艘万吨级船舶为对象,分析船体阻力与附加惯性力对拖锚淌航的影响。计算结果表明:万吨级船舶拖锚淌航初始阶段船体阻力大约为锚阻力的1/2;随着淌航距离增加、船速减小,船体阻力逐渐下降;而附加惯性力在整个淌航过程中变化不大,其约占单锚阻力的1/8。拖单锚淌航距离计算值与现有估算公式结果相比约小1节链长,拖双锚淌航距离计算值与现有估算公式结果相比差别不大。

Numerical Analysis of Ship Carrying Way with Engine Stopped and Anchor Dredging in Static Water

The ignorance of the influence of the hull resistance and the additional inertial force when estimating the travel distance of a ship after its engine stopping and anchor dropping will result in a big deviation. Taking a 10 KDWT ship for an example and introducing Newtonian law of mechanics to analyze the influences of the hull resistance and additional inertial forces on the travel distance, the results show that the hull resistance is about a half of the dragging force at the beginning, and as the ship's speed goes down the hull resistance is reduced accordingly. While the additional inertial force keeps almost the same about one eighth of the one-anchor dredging resistance during the whole process. For one-anchor dredging, the travel distance calculated by the proposed method is about one-chain-unit shorter than the traditional method, while for two-anchor dredging, little difference is seen between the proposed method and the traditional method.