|
Current Meter
A current meter is an oceanographic device for flow measurement by mechanical, tilt, acoustical or electrical means. Different reference frames In physics, one distinguishes different reference frames depending on where the observer is located, this is the basics for the Lagrangian and Eulerian specification of the flow field in fluid dynamics: The observer can be either in the Moving frame (as for a Lagrangian drifter) or in a resting frame. * Lagrangian current meters measure the displacement of an oceanographic drifter, an unmoored buoy or a non-anchored ship's actual position to the position predicted by dead reckoning. * Eulerian current meters measure current passing a resting current meter. Types Mechanical Mechanical current meters are mostly based on counting the rotations of a propeller and are thus rotor current meters. A mid-20th-century realization is the Ekman current meter which drops balls into a container to count the number of rotations. The Roberts r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumas Neyrpic Current Meter
Dumas may refer to: Places *Dumas, Arkansas, United States, a city *Dumas, Mississippi, United States, a town *Dumas, Missouri, United States, an unincorporated community *Dumas, Texas, United States, a city *Mount Dumas, a mountain on Campbell Island, New Zealand *Dumas Beach, a beach southwest of Surat, Gujarat, India *9059 Dumas, an asteroid People * Dumas (surname) * Dumas (musician) (born 1979), Canadian singer born Steve Dumas * Dumas Malone (1892–1986), Pulitzer Prize-winning American historian, biographer, and editor * Dumas or Dumarsais Simeus (born 1939), Haitian-born American businessman who ran for president of Haiti * Alexandre Dumas (1802–1870) French author and aristocrat. Fictional characters *Dumas (Kiba), Dumas (''Kiba''), a character in the Japanese anime ''Kiba'' *Duke Dumas, ruler of the vampires in the video game ''Lunar Knights'' *Dumas (DC Comics), Dumas, a DC Comics character in the Manhunter (comics)#Mark Shaw, Manhunter comics Other uses *Du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoy For Deploying Roberts Radio Current Meter - NOAA Photo Library
A buoy () is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents. Types Navigational buoys * Race course marker buoys are used for buoy racing, the most prevalent form of yacht racing and power boat racing. They delimit the course and must be passed to a specified side. They are also used in underwater orienteering competitions. * Emergency wreck buoys provide a clear and unambiguous means of temporarily marking new wrecks, typically for the first 24–72 hours. They are coloured in an equal number of blue and yellow vertical stripes and fitted with an alternating blue and yellow flashing light. They were implemented following collisions in the Dover Strait in 2002 when vessels struck the new wreck of the . * Ice marking buoys mark holes in frozen lakes and rivers so snowmobiles do not drive over the holes. * Large Navigational Buoys (LNB, or Lanby buoys) are automatic buoys over 10 m high equipped with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxwell's Equations
Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. The equations provide a mathematical model for electric, optical, and radio technologies, such as power generation, electric motors, wireless communication, lenses, radar etc. They describe how electric and magnetic fields are generated by charges, currents, and changes of the fields.''Electric'' and ''magnetic'' fields, according to the theory of relativity, are the components of a single electromagnetic field. The equations are named after the physicist and mathematician James Clerk Maxwell, who, in 1861 and 1862, published an early form of the equations that included the Lorentz force law. Maxwell first used the equations to propose that light is an electromagnetic phenomenon. The modern form of the equations in their most common formul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Faraday's Law Of Induction
Faraday's law of induction (briefly, Faraday's law) is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (emf)—a phenomenon known as electromagnetic induction. It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoids. The Maxwell–Faraday equation (listed as one of Maxwell's equations) describes the fact that a spatially varying (and also possibly time-varying, depending on how a magnetic field varies in time) electric field always accompanies a time-varying magnetic field, while Faraday's law states that there is emf (electromotive force, defined as electromagnetic work done on a unit charge when it has traveled one round of a conductive loop) on the conductive loop when the magnetic flux through the surface enclosed by the loop varies in time. Faraday's law had been discovered and one aspect of it (transformer emf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Current
An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents are primarily horizontal water movements. An ocean current flows for great distances and together they create the global conveyor belt, which plays a dominant role in determining the climate of many of Earth’s regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate for its high latitude compared to other areas at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Communications Cable
A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables laid beginning in the 1850s carried telegraphy traffic, establishing the first instant telecommunications links between continents, such as the first transatlantic telegraph cable which became operational on 16 August 1858. Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fibre technology to carry digital data, which includes telephone, Internet and private data traffic. Modern cables are typically about in diameter and weigh around for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore. Submarine cables first connected all the world's continents (except Antarctica) when Java was connected to Darwin, Northern Terr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Induction
Electromagnetic or magnetic induction is the production of an electromotive force (emf) across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction. Lenz's law describes the direction of the induced field. Faraday's law was later generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism. Electromagnetic induction has found many applications, including electrical components such as inductors and transformers, and devices such as electric motors and generators. History Electromagnetic induction was discovered by Michael Faraday, published in 1831. It was discovered independently by Joseph Henry in 1832. In Faraday's first experimental demonstration (August 29, 1831), he wrapped two wires around opposite sides of an iron ring or "torus" (an arrangement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida Strait
The Straits of Florida, Florida Straits, or Florida Strait ( es, Estrecho de Florida) is a strait located south-southeast of the North American mainland, generally accepted to be between the Gulf of Mexico and the Atlantic Ocean, and between the Florida Keys (U.S.) and Cuba. It is 93 mi (150 km) wide at the narrowest point between Key West and the Cuban shore, and has been sounded to a depth of 6,000 feet (1,800 m). The strait carries the Florida Current, the beginning of the Gulf Stream, from the Gulf of Mexico. Oil and gas Five wells were drilled in state waters south of the Florida Keys from 1947 to 1962. Gulf Oil drilled three wells in federal waters south of the Florida Keys in 1960 and 1961. All the wells were dry holes. The boundary between the Exclusive Economic Zones of the US and Cuba is halfway between Cuba and Florida, as determined by the 1977 Cuba–United States Maritime Boundary Agreement. Offshore Cuba Cuba has three producing offshore oil f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Waves
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Acoustics Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an ''acoustician'', while someone working in the field of acoustical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velocity Field
In continuum mechanics the flow velocity in fluid dynamics, also macroscopic velocity in statistical mechanics, or drift velocity in electromagnetism, is a vector field used to mathematically describe the motion of a continuum. The length of the flow velocity vector is the flow speed and is a scalar. It is also called velocity field; when evaluated along a line, it is called a velocity profile (as in, e.g., law of the wall). Definition The flow velocity ''u'' of a fluid is a vector field : \mathbf=\mathbf(\mathbf,t), which gives the velocity of an '' element of fluid'' at a position \mathbf\, and time t.\, The flow speed ''q'' is the length of the flow velocity vector :q = \, \mathbf \, and is a scalar field. Uses The flow velocity of a fluid effectively describes everything about the motion of a fluid. Many physical properties of a fluid can be expressed mathematically in terms of the flow velocity. Some common examples follow: Steady flow The flow of a fluid is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Current
A current in a fluid is the magnitude and direction of flow within that fluid, such as a liquid or a gas. Types of fluid currents include: * Air current * Boundary current * Current (stream), a current in a river or stream * Longshore current * Ocean current * Rip current * Rip tide * Subsurface currents * Tidal current * Turbidity current A turbidity current is most typically an underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in the process. T ... {{Fluiddynamics-stub Fluid dynamics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
