2. On the Optimization of Overall Performance of Rudders
スポンサーリンク
概要
- 論文の詳細を見る
Optimization scheme is attempted regarding the overall performance of rudders from wide aspects of ship hydrodynamics, i.e. maneuverability, resistance and propulsion. Two different approaches, analytical and synthetic, are adopted simultaneously. In part I, analytical procedures are developed to obtain lift and drag characteristics of rudders with given geometry, where non-linear lifting surface theory is applied. Considering that rudders are low aspect ratio wings that operate at high angle of incidence in non-uniform flow field, a new procedure for solving non-linear lifting-surface equation which implicitly includes shedding angle of free vortex to the wing plane is developed and a general method for anaiysing hydrodynamical characteristics of arbitrary aspect ratio rudders is completed. The present method does not impose any limitation on aspect ratio, angle of incidence, inflow velocity distribution nor rudder sectional profile, whereas methods so far used essentially impose limitations. Analysed forces, moments and pressure distributions agree fairly well with experimental ones. As applications of this method, it is shown that performance of a rudder as a maneuvering equipment is improved with the present method of analysis. In Part II, the optimization of rudders is pursued from resistance and propulsion points of view, where synthetic, rather than analytic, method of approach is adopted. Based on Kumano's finding (1960-61) that wave cancellation can be achieved by stern bulbs, improvement of propulsion efficiency is attempted with several unconventional rudders. Consequently, reduction of wave resistance is attained by them, and it is developed into a new type of bulb named Stern-End-Bulb. The expected reduction of resistance reaches up to 7 percent.
- 社団法人日本船舶海洋工学会の論文