Estimation of Wind Forces and Moments acting on Ships

Abstract

Various reports have been given on the study of wind forces and moments acting on ships by using wind tunnel experiments over a long time. Utilizing these results, Yamano et al. and Isherwood proposed estimation methods of wind force coefficients by linear multiple regression model in the 1970's. After that, many kinds of ships have been built all over the world, for example VLCC, PCC, LNG, and so on. The estimation methods lack reliability when wind forces and moment of such kinds of ships are predicted, since these new types of ships aren't considered in the methods.Recently Yoneta et al. proposed a estimation method consisting of several force components, which is called a physical-mathematical model. However, the applicability of this method isn't enough discussed.In the present paper, we wish to report on a new and simpler method of estimating wind force and moment coefficients acing on ships by using stepwise method which comes under linear multiple regression analysis. This estimation method was obtained after considering various ships more than previous estimation methods and the effect of wind velocity profile that some reports have already pointed out its importance in the experimental condition. As there is no way to estimate heel moment caused by strong wind, a estimation method of it is also presented in order to make use of strict simulation of maneuverability for the first time.This method has been found to possess high practical value compared with previous estimation methods.