이중덕트에 의한 U자형 감요수조의 주기조절 실험 연구

Abstract

Among the reducing devices of roll motion, the best device is an Anti-Rolling Tank(ART) in case of a working ship staying on the sea. The important point of ART design is tank tunning. Roll natural frequency of the ship is to be changed widely by load condition and location of center of gravity. Oscillation period of ART has to be altered according to the roll natural frequency of the ship. In the existing ART with a single layer duct, oscillation period is changed in narrow range. This paper suggests a method which enables wide changes in oscillation period of the ART by using a double layer duct, not a single layer duct. In the present double layer duct, duct channel is divided into two regions by a horizontal plate. A Box-type model ship has been chosen for experiments. Four cases are set on the model ship according to roll natural frequency at the same displacement. Accordingly, four U-tube type ART models applied a double layer duct are made. ART is installed in the model ship for checking roll Response Amplitude Operator(RAO) in regular waves. Through these RAO experiments, using ART with a double layer duct, it is observed that roll motion is reduced over the wide period ranges. In addition, some advantages of a double layer duct are confirmed by being compared with a single layer duct.