バラスト状態の操縦性能(舵の単独性能)

概要

論文の詳細を見る
Ship's rudder is normally fuliy immersed under the stem. However, the rudder is partially exposed on the water surface in ballast conditions. The manoeuvring prediction in ballast conditions conventionally does not take account of such rudder expose to the water surface. There has been also little research on rudder force in such condition. In this paper, the authors performed open water rudder test in several rudder exposing condition, using a large scale of rudder model. Then the following results are obtained. 1) In the prediction of rudder normal force, the actual immersing rudder area and the effective rudder aspect ratio that is twice value of geometric one should be used taking account of the miler effect of water surface. 2) However, in case of the water that falls down from the face side to the back side when the rudder is slightly immersed, the above effective aspect ratio makes over estimation of rudder normal force coefficient. 3) When the upper top is exposed on the water surface, stall phenomenon does not appear and the maximum lift coefficient significantly increases.
2012-03-25