Apparatus and method for decreasing drag force by controlling turbulent flow on hull surface of ship

A method for decreasing drag force by controlling turbulent flow on a hull surface of a ship, comprising the steps of:

• sucking and ejecting fluid flowing along the hull surface of the ship to vary turbulent field of the fluid flow;
• and
• controlling an ejection angle with respect to the hull surface of the ship, the sucked fluid being ejected at the ejection angle,
• wherein friction resistance on the hull surface is decreased by performing the sucking and ejecting and controlling steps,
• wherein said ejection angle is in the range of about 60°˜120°,
• wherein the sucking and ejecting step includes:
• providing a container with a slit;
• sucking the fluid into the container through the slit;
• and
• ejecting the sucked fluid out of the container through the slit at the ejection angle.

An apparatus for decreasing drag force by controlling turbulent flow on a hull surface of a ship, the apparatus comprising:

• a pipe housing installed on the hull surface of the ship, the pipe housing including a plurality of slits through which fluid is sucked into or ejected out;
• first plates each disposed at one end of each slit;
• second plates each disposed at the other end of each slit;
• a first rod for connecting the first plates with each other;
• a second rod for connecting the second plates with each other;
• a motor for moving the first and second rods in opposite directions, respectively.