基于CFD的内河船深浅水中操纵性预报

由于岸壁效应和浅水效应,内河船舶在限制水域作操纵运动时通常受到比在开阔水域中更大的水动力.这些水动力对船舶操纵性具有不利影响,有可能导致船舶碰撞或触底等海上事故.因此,为了在船舶设计阶段预报其操纵性能,考虑浅水效应和岸壁效应以准确计算内河船舶操纵运动水动力非常重要.本文基于CFD方法,通过对粘性绕流进行数值模拟,对长江中营运的三艘内河船舶的操纵运动水动力进行计算.首先,为了验证数值方法的可靠性,对标模KVLCC2纯横荡和纯首摇试验的水动力进行计算,并将计算结果与现有的试验数据进行对比.然后,对三艘内河船舶在不同水深下的静舵试验、纯横荡和纯首摇试验进行数值模拟,计算得到水动力及相应的线性水动力导数.最后,基于计算得到的水动力导数,获得Nomoto模型中的操纵性参数,对比分析三艘内河船舶在深浅水中的操纵性能.结果表明,本文方法可以揭示不同水深下三艘内河船舶的操纵性变化趋势.该方法可为船舶设计阶段内河船舶深浅水中的操纵性预报提供一种实用的工具.

CFD-based Manoeuvrability Prediction for Inland Ships in Deep and Shallow Waters

Inland ships in manoeuvring motions in restricted waters usually experience much larger hydrodynamic forces than in open waters due to the bank effect and shallow water effect. These forces have a detrimental influence on ship manoeuvrability and may result in marine accidents such as colli-sion or grounding. Therefore, in order to predict ship manoeuvrability in the ship design stage, it is of great importance to compute accurately the hydrodynamic forces by taking the bank effect and shallow water effect into account. In the present study, the hydrodynamic forces on three inland ships operat-ing in the Yangtze River are computed by numerically simulating the viscous flow around the manoeu-vring ships based on CFD method. Firstly, to validate the reliability of the numerical method, the com-puted hydrodynamic forces on the standard ship model KVLCC2 in pure sway and pure yaw tests are compared with available experimental data. Then, the hydrodynamic forces and the corresponding lin-ear hydrodynamic derivatives are obtained for the three inland ship models from the numerical simula-tions of the static rudder, pure sway and pure yaw tests under different water depths. Finally, the ma-noeuvrability indices in the Nomoto model are computed to analyze and compare the manoeuvring per-formance of the three ships in deep and shallow waters. It is shown that the proposed method can re-veal the changing tendencies of the manoeuvring characteristics of the three ships, providing a practi-cal tool for predicting manoeuvrability of inland ships in deep and shallow waters at the ship design stage.