|
Wing Keel
The winged keel is a sailboat keel layout first fitted on the 12-metre class yacht ''Australia II'', 1983 America's Cup winner. Design This layout was adopted by Ben Lexcen, designer of ''Australia II''. Although Ben Lexcen "had tried the winged keel idea before", there is conjecture that it was computed and designed by a Dutch aerodynamicist at the Wageningen towing tank (Netherlands Ship Model Bassin). in May 2024 A detailed article was published by the Journal of Engineering Ethics which came to the conclusion that Lexcen should not have been credited with the invention on the patent application. It also claimed that he had not been involved with the design because he had departed from Holland before the prototype work which evolved the winglets was carried out. Wings The lateral wings of Australia II are of moderate aspect ratio, forming a nearly horizontal foil, the "wing", at the bottom to provide additional effective span, in the same way as the winglets on an aircraft. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia II Winged Keel
Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It has a total area of , making it the sixth-largest country in the world and the largest in Oceania. Australia is the world's flattest and driest inhabited continent. It is a megadiverse country, and its size gives it a wide variety of landscapes and climates including deserts in the interior and tropical rainforests along the coast. The ancestors of Aboriginal Australians began arriving from south-east Asia 50,000 to 65,000 years ago, during the last glacial period. By the time of British settlement, Aboriginal Australians spoke 250 distinct languages and had one of the oldest living cultures in the world. Australia's written history commenced with Dutch exploration of most of the coastline in the 17th century. British colonisation began in 1788 with the establishment of the penal colony of New S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift-induced Drag
Lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, in aerodynamics, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or a lifting body redirecting air to cause lift and also in cars with airfoil wings that redirect air to cause a downforce. It is symbolized as D_\text, and the ''lift-induced drag coefficient'' as C_. For a constant amount of lift, induced drag can be reduced by increasing airspeed. A counter-intuitive effect of this is that, up to the speed-for-minimum-drag, aircraft need less power to fly faster. Induced drag is also reduced when the wingspan is higher, or for wings with wingtip devices. Explanation The total aerodynamic force acting on a body is usually thought of as having two components, lift and drag. By definition, the component of force parallel to the oncoming flow is called drag; and the component perpendicular to the oncomin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Inventions
This is a timeline of Australian inventions consisting of products and technology invented in Australia from pre-European-settlement in 1788 to the present. The inventions are listed in chronological order based on the date of their introduction. Australian inventions include the very old, such as woomera, and the very new, such as the scramjet, first fired at the Woomera rocket range. The Australian government has suggested that Australian inventiveness springs from the nation's geography and isolation. Perhaps due to its status as an island continent connected to the rest of the world only via air and sea, Australians have been leaders in inventions relating to both maritime and aeronautical matters, including powered flight, the black box flight recorder, the inflatable escape slide, the surf ski and the wave-piercing catamaran winged keel. Since the earliest days of European settlement, Australia's main industries have been agriculture and mining. As a result of this, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunkholing
Gunkholing is a boating term referring to a type of cruising in shallow or shoal water, meandering from place to place, spending the nights in coves. The term refers to the gunk, or mud, typical of the creeks, coves, marshes, sloughs, and rivers that are referred to as gunkholes. While not necessary, gunkholers typically seek out the serenity of isolated anchorages over the crowds of marinas and popular bays, and a minimal draft is preferred, since gunkholers tend to go as far up and into the gunkholes as possible, seeking ever more inaccessible destinations. Not all boating locales for good gunkholing. The many inlets, bays, and rivers in places like the San Juan Islands (an archipelago in the Pacific Northwest of the United States between the U.S. state of Washington and Vancouver Island, British Columbia, Canada) and the Inside Passage, (a route that extends from southeastern Alaska in the United States, through western British Columbia in Canada, to northwestern Washington st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (hull)
The draft or draught of a ship is a determined depth of the vessel below the waterline, measured vertically to its hull's lowest—its propellers, or keel, or other reference point. Draft varies according to the loaded condition of the ship. A deeper draft means the ship will have greater vertical depth below the waterline. Draft is used in under keel clearance calculations, where the draft is calculated with the available depth of water (from Electronic navigational charts) to ensure the ship can navigate safely, without grounding. Navigators can determine their draught by calculation or by visual observation (of the ship's painted load lines). Related terminology A ship's draft/draught is the "depth of the vessel below the waterline measured vertically to the lowest part of the hull, propellers, or other reference point". That is, the draft or draught is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or between a fluid and a solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path. Unlike other resistive forces, drag force depends on velocity. Drag force is proportional to the relative velocity for low-speed flow and is proportional to the velocity squared for high-speed flow. This distinction between low and high-speed flow is measured by the Reynolds number. Drag is instantaneously related to vorticity dynamics through the Josephson-Anderson relation. Examples Examples of drag include: * Net force, Net Aerodynamic force, aerodynamic or Fluid dynamics, hydrodynamic force: Drag acting opposite to the direction of movement of a solid object such as cars, aircraft, and boat hulls. * Viscou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Friction
Skin friction drag or viscous drag is a type of aerodynamic or hydrodynamic drag, which is resistant force exerted on an object moving in a fluid. Skin friction drag is caused by the viscosity of fluids and is developed from laminar drag to turbulent drag as a fluid moves on the surface of an object. Skin friction drag is generally expressed in terms of the Reynolds number, which is the ratio between inertial force and viscous force. Total drag can be decomposed into a skin friction drag component and a pressure drag component, where pressure drag includes all other sources of drag including lift-induced drag. In this conceptualisation, lift-induced drag is an artificial abstraction, part of the horizontal component of the aerodynamic reaction force. Alternatively, total drag can be decomposed into a parasitic drag component and a lift-induced drag component, where parasitic drag is all components of drag except lift-induced drag. In this conceptualisation, skin friction drag is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leeward
In geography and seamanship, windward () and leeward () are directions relative to the wind. Windward is ''upwind'' from the point of reference, i.e., towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference, i.e., along the direction towards which the wind is going. The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind, the lee side will be the "lower side". During the Age of Sail, the term ''weather'' was used as a synonym for ''windward'' in some contexts, as in the '' weather gage''. Since it captures rainfall, the windward side of a mountain tends to be wetter than the leeward side it blocks. The drier leeward area is said to be in a rain shadow. Origin The term "windward" has roots in both Low German and Old English. The word "lee", which means a place without wind, comes from the Old Norse "hle" for "cover" and has been used in marine navigation in G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wingtip Device
Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag (physics), drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft's drag. Such devices reduce drag by increasing the height of the lifting system, without greatly increasing the wingspan. Extending the span would reduce lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan (e.g. available width at Gate (airport), airport gates). Physics When a conventional wing generates lift, it also experiences lift-induced drag. Higher pressure air under the wing flows to the lower pressure surface on top at the wingtip, which results in a vortex caused by the forward motion of the aircraft. Eri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keel
The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a fluid dynamics, hydrodynamic and counterbalancing purpose as well. The keel laying, laying of the keel is often the initial step in constructing a ship. In the British and American shipbuilding traditions, this event marks the beginning date of a ship's construction. Etymology The word "keel" comes from Old English language, Old English , Old Norse , = "ship" or "keel". It has the distinction of being regarded by some scholars as the first word in the English language recorded in writing, having been recorded by Gildas in his 6th century Latin work ''De Excidio et Conquestu Britanniae'', under the spelling ''cyulae'' (he was referring to the three ships that the Saxons first arrived in). is the Latin word for "keel" and is the origin of the term careening, careen (to clean a keel and the hull in general, often by rolling the ship on its side). An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-drag ratio, which compares the benefit of lift with the air resistance of a given wing shape, as it flies. Aerodynamics is the study of wing performance in air. Equivalent Foil (fluid mechanics), foils that move through water are found on Hydrofoil, hydrofoil power vessels and Sailing hydrofoil, foiling sailboats that lift out of the water at speed and on submarines that use diving planes to point the boat upwards or downwards, while running submerged. Hydrodynamics is the study of foil performance in water. Etymology and usage The word "wing" from the Old Norse ''vængr'' for many centuries referred mainly to the foremost limb (anatomy), limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foil (fluid Mechanics)
A foil is a solid object with a shape such that when placed in a moving fluid at a suitable angle of attack the lift (force generated perpendicular to the fluid flow) is substantially larger than the drag (force generated parallel to the fluid flow). If the fluid is a gas, the foil is called an airfoil or aerofoil, and if the fluid is water the foil is called a hydrofoil. Physics of foils A foil generates lift primarily because of its shape and angle of attack. When oriented at a suitable angle, the foil deflects the oncoming fluid, resulting in a force on the foil in the direction opposite to the deflection. This force can be resolved into two components: lift and drag. This "turning" of the fluid in the vicinity of the foil creates curved streamlines which results in lower pressure on one side and higher pressure on the other. This pressure difference is accompanied by a velocity difference, via Bernoulli's principle, so for foils generating lift the resulting flowfield ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
