Resistance and Propulsion

High-fidelity numerical analysis and optimisation of ducted propeller aerodynamics and acoustics

“…Apart from marine [5] and wind energy [6] applications, the ducted propeller has been employed by several early and modern aircraft designs. During the 1950s and 1960s, the ducted propeller was extensively tested by NASA [7] [8] [9], and 2 tilt-duct prototypes, i.e.…”

Numerical analysis of propellers for electric boats using computational fluid dynamics modelling

“…A modern screw propeller with an equivalent arrangement to a pair of tandem propellers on a single shaft was patented in 1838 by James Lowe. The propeller was designed comprising one or more blades where each blade was a portion of a curve which, if continued, would produce a screw [6]. This design was then improved upon by Brunel with respect to contrarotating designs and in 1845 was implemented in the design of Great Britain to much success, which forms the basis of the fixed pitch propellers seen today.…”

“…It consists of a main hub, connected to a drive shaft, from which a number of blades are attached at a certain pitch angle. The FFP comes in two forms; monoblock propellers which are propellers cast as a single piece and built up propeller, whose blades are cast separately from the boss and then bolted or fixed in some way after machining [6]. In addition, the Wageningen B series propeller is a standard series fixed pitch propeller that was designed and tested at the Netherlands Ship Model Basin in Wageningen.…”

Propeller Performance Analysis on The Modification of Trailing Edge Shape as Anti-Singing

“…Singing is a disturbing phenomenon on the propeller. Singing often occurs in propellers with high rotational speeds [1], as well as in propellers with wide and thin blade sizes [2]. Singing can increase airborne noise and underwater noise on ships.…”

“…The cause of singing on the propeller is the resonance between the natural frequency of the propeller tip and vortex shedding on the trailing edge [2][3] [5] [6]. The most common way to deal with singing on a propeller is to sharpen the trailing edge [1]. By sharpening the trailing edge, it is hoped that the separation point will be clearer, and the wake vortices and induced forces are lower than the blunt trailing edge [2].…”