|
Oscillating Water Column
Oscillating water columns (OWCs) are a type of wave energy converter that harness energy from the oscillation of the seawater inside a chamber or hollow caused by the action of waves. OWCs have shown promise as a renewable energy source with low environmental impact. Because of this, multiple companies have been working to design increasingly efficient OWC models. OWC are devices with a semi-submerged chamber or hollow open to the sea below, keeping a trapped air pocket above a water column. Waves force the column to act like a piston, moving up and down, forcing the air out of the chamber and back into it. This continuous movement forces a bidirectional stream of high-velocity air, which is channeled through a power take-off (PTO). The PTO system converts the airflow into energy. In models that convert airflow to electricity, the PTO system consists of a bidirectional turbine. This means that the turbine always spins the same direction regardless of the direction of airflow, all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Energy Converter
Wave power is the capture of energy of wind waves to do useful mechanical work, work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power (physics), power is a wave energy converter (WEC). Waves are generated by wind passing over the sea's surface. As long as the waves propagate slower than the wind speed just above, energy is transferred from the wind to the waves. Air pressure differences between the windward and leeward sides of a wave crest (physics), crest and surface friction from the wind cause shear stress and wave growth. Wave power is distinct from tidal power, which captures the energy of the current caused by the gravitational pull of the Sun and Moon. Other forces can create ocean currents, currents, including wave breaking, breaking waves, wind, the Coriolis effect, cabbeling, and temperature and salinity differences. As of 2022, wave power is not widely employed for commercial applications, after a long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Take-off
A power take-off or power takeoff (PTO) is one of several methods for taking power from a power source, such as a running engine, and transmitting it to an application such as an attached implement or separate machine. Most commonly, it is a splined drive shaft installed on a tractor or truck allowing implements with mating fittings to be powered directly by the engine. Semi-permanently mounted power take-offs can also be found on industrial and marine engines. These applications typically use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the case of a marine application, such shafts may be used to power fire pumps. In aircraft applications, such an accessory drive may be used in conjunction with a constant speed drive. Jet aircraft have four types of PTO units: internal gearbox, external gearbox, radial drive shaft, and bleed air, which are used to power engine accessories. In some cases, aircraft power take-off systems also provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wells Turbine En
Wells most commonly refers to: * Wells, Somerset, a cathedral city in Somerset, England * Well, an excavation or structure created in the ground * Wells (name) Wells may also refer to: Places Canada *Wells, British Columbia England * Wells (Priory Road) railway station was a railway station in Wells, Somerset * Wells (Tucker Street) railway station was a railway station in Wells, Somerset * Wells (UK Parliament constituency), the UK parliamentary constituency in which the city of Wells, Somerset, is located * Wells-next-the-Sea, town and port in Norfolk ** Wells-on-Sea railway station was a railway station in Wells-next-the-Sea Scotland * Wells, Roxburghshire, a Scottish feudal barony United States *Wells, California, former name of Keene, California * Wells, Indiana *Wells, Kansas *Wells, Maine *Wells, Minnesota * Wells, Mississippi *Wells, Nevada *Wells, New York, a town **Wells (CDP), New York, a census-designated place in the town *Wells, Texas *Wells, Vermont, a New Eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wells Turbine
The Wells turbine is a low-pressure Wind turbine, air turbine that rotates continuously in one direction independent of the direction of the air flow. Its blades feature a symmetrical airfoil with its plane of symmetry in the plane of rotation and perpendicular to the air stream. It was developed for use in Oscillating Water Column wave power plants, in which a rising and falling water surface moving in an air compression chamber produces an oscillating air current. The use of this bidirectional turbine avoids the need to rectify the air stream by delicate and expensive check valve systems. Its efficiency is lower than that of a turbine with constant air stream direction and asymmetric airfoil. One reason for the lower efficiency is that symmetric airfoils have a higher drag coefficient than asymmetric ones, even under optimal conditions. Also, in the Wells turbine, the symmetric airfoil runs partly under high angle of attack (i.e., low blade speed / air speed ratio), which occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Arthur Wells
Alan Arthur Wells (1 May 1924 – 8 November 2005) was a British structural engineer. Early life He was born in Goff's Oak, Hertfordshire to Arthur John Wells, a British Oxygen Company engineer and educated at the City of London School as a day boy. He left school in 1940 to become an apprentice fitter and studied for a London University external degree via day release and weekend classes. He was awarded an intermediate B.Sc. in 1941 at the age of 17. After two years at Nottingham University College he was awarded an honours degree in Engineering, 2nd Class. He had married Rosemary Mitchell in June 1950. Honours and awards * 1942 Bayliss Prize, Institution of Civil Engineers * 1946 Miller Prize, Institution of Civil Engineers * 1955 President’s Gold Medal, Society of Engineers * 1956 Premium Award, Royal Institution of Naval Architects * 1964 Houdremont Lecture, International Institute of Welding * 1966 Hadfield Medal, Iron and Steel Institute * 1968 Larke Medal, Institute of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line (and also as the longitudinal axis). Some aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Clark Hanna (activist)
Environmental Life Force (ELF), also known as the Original ELF, was the first radical environmental group in 1977 to use explosive and incendiary devices to advance their agenda. History The original ELF was founded by John Clark Hanna. who was the only member of the group to be arrested and convicted for the use of explosives on federal property. The ELF conducted armed actions in northern California and Oregon and disbanded in 1978 following Hanna's arrest. The group claimed that warfare designed pesticides were being used on domestic crops, specifically a chemical banned after its extensive use in Vietnam. A communique to ''The Independent'' later provided the group with a frontpage story. They also called for above-ground organizations to initiate a boycott of sprayed food and for the public to criticize the process, with the following claim that. There was also an article published in ''Open Road'' in August 1977 featuring the bombing at a paper publishing company in Oregon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yoshio Masuda
Yoshio Masuda (died 2009) was a former Japanese naval commander, regarded as the father of modern wave power technology. Among other devices, the now used principle of Oscillating Water Column is regarded as his invention. It was initially used for small-scale navigation buoys. See also *Wave power Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated by wind p ... References Japanese military personnel Wave power 2009 deaths Year of birth missing {{japan-mil-bio-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breakwater (structure)
A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Part of a coastal management system, breakwaters are installed to minimize erosion, and to protect anchorages, helping isolate vessels within them from marine hazards such as prop washes and wind-driven waves. A breakwater, also known in some contexts as a jetty, may be connected to land or freestanding, and may contain a walkway or road for vehicle access. On beaches where longshore drift threatens the erosion of beach material, smaller structures on the beach, usually perpendicular to the water's edge, may be installed. Their action on waves and current is intended to slow the longshore drift and discourage mobilisation of beach material. In this usage they are more usually referred to as groynes. Purposes Breakwaters reduce the intensity of wave action in inshore waters and thereby provide safe harbourage. Breakwaters may also be small structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
