Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems.
Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfares. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, produce steam to propel warships and icebreakers; commercial application, attempted late that decade, failed to catch on. Electric motors using battery packs have been used for propulsion on submarines and electric boats and have been proposed for energy-efficient propulsion.Development in liquefied natural gas (LNG) fueled engines are gaining recognition for their low emissions and cost advantages. Stirling engines, which are quieter, smoother running, propel a number of small submarines in order to run as quietly as possible. Its design is not used in civilian marine application due to lower total efficiency than internal combustion engines or power turbines.
Until the application of the coal-fired steam engine to ships in the early 19th century, oars or the wind were the principal means of watercraft propulsion. Merchant ships predominantly used sail, but during periods when naval warfare depended on ships closing to ram or to fight hand-to-hand, galley were preferred for their manoeuvrability and speed.
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The main objective of the course is to provide an overview of space propulsion systems. The course will also describe the basic design principles of propulsion systems.
This course is an introduction to the alignment of enterprise needs with the possibilities offered by Information Technology (IT). Using a simulated business case, we explore how to define the require
Air-independent propulsion (AIP), or air-independent power, is any marine propulsion technology that allows a non-nuclear submarine to operate without access to atmospheric oxygen (by surfacing or using a snorkel). AIP can augment or replace the diesel-electric propulsion system of non-nuclear vessels. Modern non-nuclear submarines are potentially stealthier than nuclear submarines; although some modern submarine reactors are designed to rely on natural circulation, most naval nuclear reactors use pumps to constantly circulate the reactor coolant, generating some amount of detectable noise.
Wärtsilä Oyj Abp (ˈʋærtsilæ), trading internationally as Wärtsilä Corporation, is a Finnish company which manufactures and services power sources and other equipment in the marine and energy markets. The core products of Wärtsilä include technologies for the energy sector, including gas, multi-fuel, liquid fuel and biofuel power plants and energy storage systems; and technologies for the marine sector, including cruise ships, ferries, fishing vessels, merchant ships, navy ships, special vessels, tugs, yachts and offshore vessels.
Any vehicle used in or on water as well as underwater, including boats, ships, yachts, hovercraft and submarines, is a watercraft (: watercraft), also known as a water vessel or waterborne vessel. A watercraft usually has a propulsive capability (whether by sail, oar, paddle, or engine) and hence is distinct from a stationary device, such as a pontoon, that merely floats. Most watercraft may be described as either a ship or a boat. However, numerous items, including surfboards, underwater robots, seaplanes and torpedoes, may be considered neither ships nor boats.
Numerical simulation of tip vortex cavitation (TVC) remains a challenging task in a variety of applica-tions, such as axial turbines and pumps as well as marine propellers. Although it is well known that TVC is highly sensitive to gas content, be it dissol ...
Predicting particle transport in turbulent flows has a plethora of applications, some of which are: the transport of atmospheric aerosols, the deposition of blood cells in the arteries of human bodies and the atomization of fuel droplets in combustion cham ...
EPFL2022
In this manuscript we describe the realization of a minimal hybrid microswimmer, composed of a ferromagnetic nanorod and a paramagnetic microsphere. The unbounded pair is propelled in water upon application of a swinging magnetic field that induces a perio ...