Numerical Analysis of Hydrodynamic Performance of Finite Span Hydrofoil

有限跨度水翼水动力性能数值分析

• 批准号: 02302054
• 负责人: KATO Hiroharu
• 金额: $ 6.72万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02302054/
• 关键词: Finite Span Foil; Finite Difference Method; Lifting Body Theory; Cavitation; Free Surface; Tip Vortex; CFD; 有限幅直進翼

Made were the numerical and experimental investigations on the hydrodynamic performance and flow situations of a finite span hydrofoil. The following results were obtained :The lift and drag forces and the pressure distribution obtained by the lifting body theory agreed well with those of the experiments unless the large boundary layer separation occurred on the hydrofoil surface.This theory, however, could not argue the details of the flow situations such as boundary layer and its relation to the tip vortex.Two kinds of finite difference calculations were made with a low Reynolds number of 1, 000. Some kinds of calculation conditions were selected such as with free surface and with cavitation. The results were compared and discussed in detail with the experimental ones. As a result the future works of the CFD research were clarified on the hydrodynamic study of finite span hydrofoils.The calculation of a hydrofoil under a free surface showed the wave-making due to the foil and the lift force decrease due to the free surface.It was shown that the tip vortex had two cores caused by the two boundary layers on the foil upper and lower surfaces, respectively. The rolling-up to the tip vortex and the tip vortex separation were also calculated.The calculated cavitation on the foil surface had similar appearance to that of the experiments although the quantitative agreement could not be obtained because of the large difference in the Reynolds numbers.The measurements showed that the tip vortex had a very small radius of 1% the maximum chord length and a high rotation speed of over 0.6 times the uniform flow velocity. A solution adaptive grid, multi-grid system or some modeling of the tip vortex might be required in addition to the turbulence model, in order to calculate a high Reynolds number flow and argue the tip vortex in detail.

对有限跨度水翼的水动力性能和流动情况进行了数值和实验研究。得到如下结果：除非水翼表面发生大的边界层分离，否则升力体理论得到的升力、阻力和压力分布与实验结果吻合较好。然而，该理论无法论证细节边界层等流动情况及其与尖端涡的关系。在低雷诺数1, 000下进行了两种有限差分计算。选择了自由表面和空化等几种计算条件。将结果与实验结果进行了详细的比较和讨论。从而明确了CFD研究的未来工作方向是有限跨度水翼的水动力研究。自由表面下的水翼的计算表明，由于水翼而产生波浪，并且由于自由表面而导致升力减小。结果表明，尖端涡有两个核心，分别由箔上表面和下表面上的两个边界层引起。还计算了尖端涡的卷起和尖端涡的分离。计算的箔表面空化与实验的空化具有相似的外观，尽管由于雷诺数差异较大而无法获得定量一致。测量结果表明，尖端涡流的半径非常小，仅为最大弦长的 1%，并且旋转速度高达均匀流速的 0.6 倍以上。除了湍流模型之外，可能还需要自适应网格、多网格系统或尖端涡流的某种建模，以便计算高雷诺数流并详细论证尖端涡流。