| Summary: | 碩士 === 國立臺灣大學 === 造船及海洋工程學研究所 === 89 === The turbulent flow around rudders is computed and analyzed by solving the Reynolds-averaged Navier-Stokes equations to investigate the hydrodynamic performance, such as lift, drag, stock moment and stall angle, of several rudders used on high-speed craft with various geometric parameters. A second order finite volume method with multi-block structured grid system is applied to discretize the equation and space respectively. The standard k-ε turbulent model is employed to take account of the turbulent effect. Good agreements are obtained between the computational and experimental results.
The present studies focus on the performance analysis of several practical rudders with NACA 00XX, NACA 16, NACA 66, WedgeXX, EllipseXX and RectangleXX profiles (see Appendix A and B) at Reynolds number Re of 106. Three basic non-dimensional coefficients: lift CL(α), drag CD(α) and moment CM(α), being functions of the angle of attack α of the rudder are evaluated to investigate the influences of Reynolds number, profile shape, aspect ratio, taper ratio and profile thickness, on the performance of high-speed craft rudders. Also, the position of the rudder shaft center was varied along the nose-tail line, in order to find out the stock location of minimum moment for each rudder. Furthermore, the pressure coefficient Cp and the shear stress distribution on each rudder surface are presented. In general, the NACA 00XX rudders show a better performance compared to other calculated rudders in this work.
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