以KCS船和KP505桨为计算对象,采用RANS方法和VOF模型,开展了考虑自由液面的实船自航试验数值模拟。首先进行KCS船模自航点工况下的流场计算和KP505桨的敞水性能计算,计算结果与试验值吻合较好,验证了计算方法的可行性。本文分析了船体阻力、波形和速度场的尺度效应,获得了实船的推进因子。根据数值自航试验曲线确定了自航点,进而插值计算得到实船推进因子,并分析发现自航点转速和伴流分数尺度效应明显。结果表明:实船伴流分数要小于船模,自航点转速要大于船模。
In this study,we adopt the Reynolds-averaged Navier-Stokes( RANS) method and volume of fluid( VOF) model to carry out a numerical simulation of a self-propulsion test of a full-scale ship,considering a free surface on a KCS ship and KP505 propeller. First,we performed a numerical computation of a model-scale KCS under the conditions of a self-propulsion point and open-water propeller performance. The calculated results were in good agreement with the experimental data,thereby verifying the feasibility of the calculation method. Next,we analyzed the scale effect on the ship resistance,wave pattern,and velocity field,and obtained the propulsion factors of a full-scale ship. Based on the curves of the numerical self-propulsion test,we confirmed the self-propulsion point of the full-scale ship. Using the interpolation method,we identified the propulsion factors and found the scale effect of the rotational speed at the self-propulsion point and wake fraction to be obvious. The results show that the wake fraction of a full-scale ship is smaller than that of a model ship and its rotational speed at the self-propulsion point is greater.