Accession Number : ADD017598
Title : Twisted Rudder for a Vessel.
Descriptive Note : Patent, Filed 13 Oct 93, patented 16 May 95
Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC
Personal Author(s) : Shen, Young T
Report Date : 16 May 1995
Pagination or Media Count : 20
Abstract : Ship rudders are subjected to propeller induced velocities and induced flow angles that vary along the rudder span and chord. Because of non-zero onset flow angles, a suction pressure peak is formed at or near the leading edge of the rudder where early cavitation occurs. The present invention is directed to a rudder and method for minimizing early cavitation and related ship vibration and for thus improving acoustic and hydrodynamic performance thereof. The rudder of the present invention is twisted so as to have profiles along its entire span that are aligned with propeller induced non-zero onset flow angles into the rudder plane. The twist of the rudder sections vary in the spanwise direction, that is, the twist angle of one rudder sections may vary relative to the twist angle of adjacent or remaining rudder sections, such that the rudder experiences substantially zero angles of attack along the span.
Descriptors : *MARINE RUDDERS, *PATENTS, ANGLES, PEAK VALUES, VIBRATION, SHIPS, HYDRODYNAMIC CHARACTERISTICS, PERFORMANCE(ENGINEERING), ANGLE OF ATTACK, PRESSURE, LEADING EDGES, FLOW, CHARTS, SUCTION, MARINE PROPELLERS, ACOUSTIC PROPERTIES, TWIST(MOTION), CAVITATION
Subject Categories : Marine Engineering
Distribution Statement : APPROVED FOR PUBLIC RELEASE