duct with hydro-foil section attached on ship stern

摘要

Provided is a duct mounted on a stern and having an airfoil cross-section which is a circular duct mounted in front of a stern propeller having a radius R, has an airfoil cross-section, has 0.7R as a radius of a rear end portion, and has 14° as size of a receiving angle. According to the present invention, by rectifying and accelerating flow of a flow field introduced inside a duct and passing the duct, pressure recovery of a stern can be promoted thus improving ship body resistance, and a propulsive performance of a propeller can be improved by a change in counter current introduced to the propeller. Also, by designing a shape of a cross-section in an airfoil type and appropriately designing a receiving angle of a duct with respect to the introduced flow field, drag of the duct itself, which is an additional object, can be minimized, and additional thrust of the duct itself can be expected. Also, the shape of the duct is relatively simple and the duct can be installed by simply attaching it on a stern, thereby being conveniently manufactured and installed, being inexpensive, and being applicable to both new and existing types of ships.