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Bank Effect
The bank effect (channel effect, bank suction, bank cushion, stern suction, ship-bank interaction) is the tendency of the stern of a ship to swing toward the near bank when operating in a river or constricted waterway. Paywall Phenomenon The asymmetric flow around a ship induced by the vicinity of banks causes pressure differences (Bernoulli's principle) between port and starboard sides. As a result, a lateral force will act on the ship, mostly directed towards the closest bank, as well as a yawing moment pushing her bow towards the centre of the waterway. The squat effect increases due to the decreased blockage. This phenomenon depends on many parameters, such as bank shape, water depth, ship-bank distance, ship properties, ship speed and propeller action. A reliable estimation of bank effects is important for determining the limiting conditions in which a ship can safely navigate a waterway. Examples It was cited as a possible cause of the 2021 Suez Canal obstructio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stern
The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Originally, the term only referred to the aft port section of the ship, but eventually came to refer to the entire back of a vessel. The stern end of a ship is indicated with a white navigation light at night. Sterns on European and American wooden sailing ships began with two principal forms: the ''square'' or ''transom'' stern and the ''elliptical'', ''fantail'', or ''merchant'' stern, and were developed in that order. The hull sections of a sailing ship located before the stern were composed of a series of U-shaped rib-like frames set in a sloped or "cant" arrangement, with the last frame before the stern being called the ''fashion timber(s)'' or ''fashion piece(s)'', so called for "fashioning" the after part of the ship. This frame is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity, and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to world population growth. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a ship-rigged sailing ship with three or more masts, each of which is square-rigged. As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterway
A waterway is any navigable body of water. Broad distinctions are useful to avoid ambiguity, and disambiguation will be of varying importance depending on the nuance of the equivalent word in other languages. A first distinction is necessary between maritime shipping routes and waterways used by inland water craft. Maritime shipping routes cross oceans and seas, and some lakes, where navigability is assumed, and no engineering is required, except to provide the draft for deep-sea shipping to approach seaports (channels), or to provide a short cut across an isthmus; this is the function of ship canals. Dredged channels in the sea are not usually described as waterways. There is an exception to this initial distinction, essentially for legal purposes, see under international waters. Where seaports are located inland, they are approached through a waterway that could be termed "inland" but in practice is generally referred to as a "maritime waterway" (examples Seine Maritime, Loir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Financial Times
The ''Financial Times'' (''FT'') is a British daily newspaper printed in broadsheet and published digitally that focuses on business and economic current affairs. Based in London, England, the paper is owned by a Japanese holding company, Nikkei, with core editorial offices across Britain, the United States and continental Europe. In July 2015, Pearson sold the publication to Nikkei for £844 million (US$1.32 billion) after owning it since 1957. In 2019, it reported one million paying subscriptions, three-quarters of which were digital subscriptions. The newspaper has a prominent focus on financial journalism and economic analysis over generalist reporting, drawing both criticism and acclaim. The daily sponsors an annual book award and publishes a " Person of the Year" feature. The paper was founded in January 1888 as the ''London Financial Guide'' before rebranding a month later as the ''Financial Times''. It was first circulated around metropolitan London by James Sherid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paywall
A paywall is a method of restricting access to content, with a purchase or a paid subscription, especially news. Beginning in the mid-2010s, newspapers started implementing paywalls on their websites as a way to increase revenue after years of decline in paid print readership and advertising revenue, partly due to the use of ad blockers. In academics, research papers are often subject to a paywall and are available via academic libraries that subscribe. Paywalls have also been used as a way of increasing the number of print subscribers; for example, some newspapers offer access to online content plus delivery of a Sunday print edition at a lower price than online access alone. Newspaper websites such as that of ''The Boston Globe'' and ''The New York Times'' use this tactic because it increases both their online revenue and their print circulation (which in turn provides more ad revenue). History In 1996, ''The Wall Street Journal'' set up and has continued to maintain a " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernoulli's Principle
In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after the Swiss mathematician and physicist Daniel Bernoulli, who published it in his book ''Hydrodynamica'' in 1738. Although Bernoulli deduced that pressure decreases when the flow speed increases, it was Leonhard Euler in 1752 who derived Bernoulli's equation in its usual form. The principle is only applicable for isentropic flows: when the effects of irreversible processes (like turbulence) and non-adiabatic processes (e.g. thermal radiation) are small and can be neglected. Bernoulli's principle can be applied to various types of fluid flow, resulting in various forms of Bernoulli's equation. The simple form of Bernoulli's equation is valid for incompressible flows (e.g. most liquid flows and gases moving at low Mach number). More advanced forms may be applied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degrees Of Freedom (engineering)
In physics, the degrees of freedom (DOF) of a mechanical system is the number of independent parameters that define its configuration or state. It is important in the analysis of systems of bodies in mechanical engineering, structural engineering, aerospace engineering, robotics, and other fields. The position of a single railcar (engine) moving along a track has one degree of freedom because the position of the car is defined by the distance along the track. A train of rigid cars connected by hinges to an engine still has only one degree of freedom because the positions of the cars behind the engine are constrained by the shape of the track. An automobile with highly stiff suspension can be considered to be a rigid body traveling on a plane (a flat, two-dimensional space). This body has three independent degrees of freedom consisting of two components of translation and one angle of rotation. Skidding or drifting is a good example of an automobile's three independent degrees ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yaw Angle
The Euler angles are three angles introduced by Leonhard Euler to describe the orientation of a rigid body with respect to a fixed coordinate system.Novi Commentarii academiae scientiarum Petropolitanae 20, 1776, pp. 189–207 (E478PDF/ref> They can also represent the orientation of a mobile frame of reference in physics or the orientation of a general basis in 3-dimensional linear algebra. Alternative forms were later introduced by Peter Guthrie Tait and George H. Bryan intended for use in aeronautics and engineering. Chained rotations equivalence Euler angles can be defined by elemental geometry or by composition of rotations. The geometrical definition demonstrates that three composed ''elemental rotations'' (rotations about the axes of a coordinate system) are always sufficient to reach any target frame. The three elemental rotations may be extrinsic (rotations about the axes ''xyz'' of the original coordinate system, which is assumed to remain motionless), or intrinsic ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squat Effect
The squat effect is the hydrodynamic phenomenon by which a vessel moving through shallow water creates an area of reduced pressure that causes the ship to increase its draft and thereby be closer to the seabed than would otherwise be expected. This phenomenon is caused by the water flow which accelerates as it passes between the hull and the seabed in confined waters, the increase in water velocity causing a resultant reduction in pressure. Squat effect from a combination of vertical sinkage and a change of trim may cause the vessel to dip towards the stern or towards the bow. This is understood to be a function of the Block coefficient of the vessel concerned, finer lined vessels Cb 0.7 squatting by the head or bow. Squat effect is approximately proportional to the square of the speed of the ship. Thus, by reducing speed by half, the squat effect is reduced by a factor of four. Squat effect is usually felt more when the depth/draft ratio is less than four or when sailing cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are specially shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft (ship), propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
