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Undercompressive Shock Wave
An undercompressive shock wave is a shock wave that does not fulfill the Peter Lax conditions. Details Ordinary shock waves are compressive, that is, they fulfill the Lax conditions: the characteristic speed (in air, the speed of sound) behind the shock is greater than that of the shock itself, which is greater than the characteristic speed in front of the shock. The characteristic speed is the speed of small, travelling perturbations. These conditions seem to be necessary for a shock wave to remain and not decay. If the peak of a wave moves faster than at its base, then the wave front becomes self-sharpening and eventually becomes a nearly discontinuous shock, a sharp wave front which remains so when it travels. A shock wave is undercompressive if the Lax conditions are not fulfilled. A sharp wave front may remain sharp whilst travelling even when perturbations behind the front travel slower than it. An experiment can be made to show this with travelling liquid steps : a thic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Lax
Peter David Lax (born Lax Péter Dávid; 1 May 1926) is a Hungarian-born American mathematician and Abel Prize laureate working in the areas of pure and applied mathematics. Lax has made important contributions to integrable systems, fluid dynamics and shock waves, solitonic physics, hyperbolic conservation laws, and mathematical and scientific computing, among other fields. In a 1958 paper Lax stated a conjecture about matrix representations for third order hyperbolic polynomials which remained unproven for over four decades. Interest in the "Lax conjecture" grew as mathematicians working in several different areas recognized the importance of its implications in their field, until it was finally proven to be true in 2003. Life and education Lax was born in Budapest, Hungary to a Jewish family. Lax began displaying an interest in mathematics at age twelve, and soon his parents hired Rózsa Péter as a tutor for him. His parents Klara Kornfield and Henry Lax were both physici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undercompressive Shock Wave
An undercompressive shock wave is a shock wave that does not fulfill the Peter Lax conditions. Details Ordinary shock waves are compressive, that is, they fulfill the Lax conditions: the characteristic speed (in air, the speed of sound) behind the shock is greater than that of the shock itself, which is greater than the characteristic speed in front of the shock. The characteristic speed is the speed of small, travelling perturbations. These conditions seem to be necessary for a shock wave to remain and not decay. If the peak of a wave moves faster than at its base, then the wave front becomes self-sharpening and eventually becomes a nearly discontinuous shock, a sharp wave front which remains so when it travels. A shock wave is undercompressive if the Lax conditions are not fulfilled. A sharp wave front may remain sharp whilst travelling even when perturbations behind the front travel slower than it. An experiment can be made to show this with travelling liquid steps : a thic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compressive Shock Wave
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elongation which is also known as deformation, like the stretching of an elastic band, it is called tensile stress. But, when the forces result in the compression of an object, it is called compressive stress. It results when forces like tension or compression act on a body. The greater this force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Therefore, stress is measured in newton per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marangoni Effect
The Marangoni effect (also called the Gibbs–Marangoni effect) is the mass transfer along an interface between two phases due to a gradient of the surface tension. In the case of temperature dependence, this phenomenon may be called thermo-capillary convection (or Bénard–Marangoni convection). History This phenomenon was first identified in the so-called "tears of wine" by physicist James Thomson (Lord Kelvin's brother) in 1855. The general effect is named after Italian physicist Carlo Marangoni, who studied it for his doctoral dissertation at the University of Pavia and published his results in 1865. A complete theoretical treatment of the subject was given by J. Willard Gibbs in his work ''On the Equilibrium of Heterogeneous Substances'' (1875-8). Mechanism Since a liquid with a high surface tension pulls more strongly on the surrounding liquid than one with a low surface tension, the presence of a gradient in surface tension will naturally cause the liquid to flow away fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerald B
Gerald is a male Germanic given name meaning "rule of the spear" from the prefix ''ger-'' ("spear") and suffix ''-wald'' ("rule"). Variants include the English given name Jerrold, the feminine nickname Jeri and the Welsh language Gerallt and Irish language Gearalt. Gerald is less common as a surname. The name is also found in French as Gérald. Geraldine is the feminine equivalent. Given name People with the name Gerald include: Politicians * Gerald Boland, Ireland's longest-serving Minister for Justice * Gerald Ford, 38th President of the United States * Gerald Gardiner, Baron Gardiner, Lord Chancellor from 1964 to 1970 * Gerald Häfner, German MEP * Gerald Klug, Austrian politician * Gerald Lascelles (other), several people * Gerald Nabarro, British Conservative politician * Gerald S. McGowan, US Ambassador to Portugal * Gerald Wellesley, 7th Duke of Wellington, British diplomat, soldier, and architect Sports * Gerald Asamoah, Ghanaian-born German football player * Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter D
Peter may refer to: People * List of people named Peter, a list of people and fictional characters with the given name * Peter (given name) ** Saint Peter (died 60s), apostle of Jesus, leader of the early Christian Church * Peter (surname), a surname (including a list of people with the name) Culture * Peter (actor) (born 1952), stage name Shinnosuke Ikehata, Japanese dancer and actor * ''Peter'' (album), a 1993 EP by Canadian band Eric's Trip * ''Peter'' (1934 film), a 1934 film directed by Henry Koster * ''Peter'' (2021 film), Marathi language film * "Peter" (''Fringe'' episode), an episode of the television series ''Fringe'' * ''Peter'' (novel), a 1908 book by Francis Hopkinson Smith * "Peter" (short story), an 1892 short story by Willa Cather Animals * Peter, the Lord's cat, cat at Lord's Cricket Ground in London * Peter (chief mouser), Chief Mouser between 1929 and 1946 * Peter II (cat), Chief Mouser between 1946 and 1947 * Peter III (cat), Chief Mouser between 1947 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandra Troian
Sandra Marina Troian (born 1957) is an American applied physicist known for her research on fluid dynamics, quasicrystals, surface science, thin films, microfluidics, and spacecraft micropropulsion. She is a professor of Applied Physics, Aeronautics, and Mechanical Engineering in the Division of Engineering and Applied Science of the California Institute of Technology (Caltech), and head of the Laboratory of Interfacial and Small Scale Transport in the Department of Applied Physics and Materials Science at Caltech. Research The Thompson and Troian slip condition, a model for nonlinear flow of liquids at liquid-solid interfaces, is named for Troian's discovery of this model with physicist Peter Thompson, which they published in ''Nature'' in 1997. Her research has also included methods for controlling microscopic fluid droplets using a combination of chemical patterns and temperature variations on surfaces, rather than by using microfluidic pumps, published in ''Nature'' in 2000. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
