雷诺相似船模预报实船推进因子的数值方法

Accurately predicting the propulsion factors of a ship using a Reynolds-similarity ship model

为了克服船模预报实船推进因子中的尺度效应,通过引入虚流体运动粘性系数,在数值计算中实现了缩尺船模与实船的雷诺数相似.根据船体兴波作用对推进因子影响甚小的基本分析结论,运用RANS方程和RNGk-ε湍流模型,对一条缩尺比为20的雷诺相似船模进行了不考虑船体兴波影响的自航数值试验计算,通过对数值相似自航船模自航点和推进因子的数值计算,预报了实船的实效伴流分数和推力减额分数,所得结果与试验吻合较好,表明了该文的实船推进因子预报方法可以消除船模与实船之间固有的尺度效应,具有较强的工程实用性.

In order to eliminate the effects of scale on data obtained from a ship＇s model when compared to the results from the actual ship, the Reynolds similarity criterion was achieved between a scale-reduced ship model and an actual ship in numerical calculations by introduction of virtual fluid kinematic viscosity factor. A simulated selfpropulsion experiment on a 1：20 scale Reynolds-similarity ship model was carried out, in which the wave making of the ship model had little influence on the propulsion factors so that wave resistance could be ignored in the calculation. The self-propulsion point and propulsion factors of the Reynolds-similarity ship model were numerically calculated; therefore the effective wake factor and thrust deduction factor of actual ship were numerically predicted and the results were in good agreement with data from the actual ship. It is showed that this method for predicting the propulsion factors of a ship is able to eliminate the scale effect between the ship and its model, and is useful for engineering.