| 摘要 |
PURPOSE:To maximize the rolling reduction effect without sacrifice of save energy effect, by setting the sail angle while considering not only the thrust due to the sail but also the rolling reduction effect due to the sail. CONSTITUTION:The relative wind direction thetaA(t) and the relative wind speed VA(t) of sail varying periodically are called for every time interval DELTAt to obtain the thrust FX(t) due to the sail and the damping energy EX(t) due to the sail for various imaginary sail angles thetasi and the average -FX(t), -EX(t) for single period. Then the final sail angle thetas is obtained from the imaginary sail angles thetaSX, thetaSY where the averages will be at the maximum to set the sail angle. When setting the final sail angle thetaS, the factors m, n for thetaSX, thetaSY are inputted properly to set the sail angle thetaS between both imaginary sail angles thus to achieve the rolling reduction effect while producing the thrust due to the sail. |
