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Michelson–Sivashinsky Equation
In combustion, Michelson–Sivashinsky equation describes the evolution of a premixed flame front, subjected to the Darrieus–Landau instability, in the small heat release approximation. The equation was derived by Gregory Sivashinsky in 1977, who along the Daniel M. Michelson, presented the numerical solutions of the equation in the same year. Let the planar flame front, in a uitable frame of reference be on the xy-plane, then the evolution of this planar front is described by the amplitude function u(\mathbf x,t) (where \mathbf x=(x,y)) describing the deviation from the planar shape. The Michelson–Sivashinsky equation, reads as :\frac + \frac(\nabla u)^2 - \nu \nabla^2 u - \frac \int , \mathbf k, e^u (\mathbf x,t) d\mathbf kd\mathbf x'=0, where \nu is a constant. Incorporating also the Rayleigh–Taylor instability of the flame, one obtains the Rakib–Sivashinsky equation (named after Z. Rakib and Gregory Sivashinsky), :\frac + \frac(\nabla u)^2 - \nu \nabla^2 u - \frac \ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While activation energy must be supplied to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. The study of combustion is known as combustion science. Combustion is often a complicated sequence of elementary reaction, elementary Radical (chemistry), radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darrieus–Landau Instability
The Darrieus–Landau instability, or density fingering, refers to an instability of chemical fronts propagating into a denser medium, named after Georges Jean Marie Darrieus and Lev Landau. It is a key Combustion instability#Classification of combustion instabilities, instrinsic flame instability that occurs in premixed flames, caused by density variations due to thermal expansion of the gas produced by the combustion process. In simple terms, stability inquires whether a steadily propagating plane sheet with a discontinuous jump in density is stable or not. The analysis behind the Darrieus–Landau instability considers a planar, premixed flame front subjected to very small perturbations. It is useful to think of this arrangement as one in which the unperturbed flame is stationary, with the reactants (fuel and oxidizer) directed towards the flame and perpendicular to it with a velocity u1, and the burnt gases leaving the flame also in a perpendicular way but with velocity u2. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gregory Sivashinsky
Gregory I. Sivashinsky (also known as Grisha) is a professor at Tel Aviv University, working in the field of combustion and theoretical physics. Biography Sivashinsky was born in Moscow to Israel and Tatiana Sivashinsky. He is married to Terry Sivashinsky. He finished his master's degree at Moscow State University in 1967 and worked as a research assistant there until 1971. He emigrated to Israel in 1971. He was a pupil of Grigory Isaakovich Barenblatt and Yakov Borisovich Zel'dovich. He completed his PhD at Technion – Israel Institute of Technology in 1973 and worked as a lecturer there for two years. He joined Tel Aviv University in 1974 and settled there. He is the recipient of Ya.B. Zeldovich Gold Medal from The Combustion Institute and a fellow of The Combustion Institute The Combustion Institute is an educational non-profit, international, scientific and engineering society whose purpose is to promote research in combustion science. The institute was established in 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh–Taylor Instability
The Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an Interface (chemistry), interface between two fluids of different densities which occurs when the lighter fluid is pushing the heavier fluid. Philip Drazin, Drazin (2002) pp. 50–51. Examples include the behavior of water suspended above oil in the gravity of Earth, mushroom clouds like those from volcanic eruptions and atmospheric nuclear explosions, supernova explosions in which expanding core gas is accelerated into denser shell gas, merging binary quantum fluids in metastable configuration, instabilities in plasma fusion reactors and inertial confinement fusion. Concept Water suspended atop oil is an everyday example of Rayleigh–Taylor instability, and it may be scientific modeling, modeled by two completely plane-parallel layers of immiscible fluid, the denser fluid on top of the less dense one and both subject to the Earth's gravity. The Mechanical equili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uriel Frisch
Uriel Frisch (born in Agen, in France, on December 10, 1940) is a French mathematical physicist known for his work on fluid dynamics and turbulence. Biography From 1959 to 1963 Frisch was a student at the École Normale Supérieure. Early in his graduate studies, he became interested in turbulence, under the mentorship of Robert Kraichnan, a former assistant to Albert Einstein. Frisch earned a Ph.D. in 1967 from the University of Paris, and since then he has worked at the French National Centre for Scientific Research (CNRS). He retired in 2006, and became a director of research emeritus at CNRS.Curriculum vitae retrieved 2012-03-05. Frisch's wife Hélène is also a physicist, and the grand daughter of mathematician Paul Lév ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michel Hénon
Michel Hénon (; 23 July 1931, Paris – 7 April 2013, Nice) was a French mathematician and astronomer. He worked for a long time at the Nice Observatory. In astronomy, Hénon is well known for his contributions to stellar dynamics. In the late 1960s and early 1970s he made important contributions on the dynamical evolution of star clusters, in particular globular clusters. He developed a numerical technique using Monte Carlo methods to follow the dynamical evolution of a spherical star cluster much faster than the so-called ''n''-body methods. In mathematics, he is well known for the Hénon map, a simple discrete dynamical system that exhibits chaotic behavior. He published a two-volume work on the restricted three-body problem. In 1978 he was awarded the '' Prix Jean Ricard''. See also * N-body units References External links Hénon's publications(a partial list from NASA Astrophysics Data System). A discussionof Hénon's equation, contains further links. Simulationof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John W
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died ), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (died ), one of the twelve apostles of Jesus Christ * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope John (disambigu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guy Joulin
Guy Joulin is a French scientist at Aix-Marseille University who works in the field of combustion. Biography Guy Joulin obtained his PhD degree from University of Poitiers in 1979 under the supervision of Paul Clavin. Joulin is the recipient of the CNRS Silver Medal The CNRS Silver Medal is a scientific award given every year to about fifteen researchers by the French National Centre for Scientific Research (CNRS). It is awarded to a researcher for "the originality, quality and importance of their work, re ... (1996). See also References External links * French fluid dynamicists Living people Fellows of the Combustion Institute Year of birth missing (living people) University of Poitiers alumni {{France-scientist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Clavin
Paul Clavin is a French scientist at Aix-Marseille University, working in the field of combustion and statistical mechanics. He is the founder of Institute for Research on Nonequilibrium Phenomena (IRPHE). Biography Paul Clavin obtained his first degree at ENSMA and then a Master's degree in Mathematics and Plasma Physics. For his PhD, he joined Ilya Prigogine in Brussels from 1967 to 1970 and then returned to Poitiers. Paul Clavin moved to Aix-Marseille University in the late 1970s and created the combustion research group. Clavin served as the chair of the Physical Mechanics at Institut Universitaire de France from 1993 to 2004 and the administrator from 2000 to 2005. He received Ya.B. Zeldovich Gold Medal from The Combustion Institute in 2014 and a fellow of The Combustion Institute. A workshop titled ''Out-of-Equilibrium Dynamics'' was conducted in 2012 in honor of Clavin's 70th birthday. He is the recipient of Grand Prix award from French Academy of Sciences in 1998 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kuramoto–Sivashinsky Equation
In mathematics, the Kuramoto–Sivashinsky equation (also called the KS equation or flame equation) is a fourth-order nonlinear partial differential equation. It is named after Yoshiki Kuramoto and Gregory Sivashinsky, who derived the equation in the late 1970s to model the diffusive–thermal instabilities in a laminar flame front. It was later and independently derived by G. M. Homsy and A. A. Nepomnyashchii in 1974, in connection with the stability of liquid film on an inclined plane and by R. E. LaQuey et. al. in 1975 in connection with trapped-ion instability. The Kuramoto–Sivashinsky equation is known for its chaotic behavior. Definition The 1d version of the Kuramoto–Sivashinsky equation is :u_t + u_ + u_ + \frac\left(u^2\right)_x = 0 An alternate form is :v_t + v_ + v_ + v v_x = 0 obtained by differentiating with respect to x and substituting v = u. This is the form used in fluid dynamics applications. The Kuramoto–Sivashinsky equation can also be generalized to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion) and (the study of water and other liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moment (physics), moments on aircraft, determining the mass flow rate of petroleum through pipeline transport, pipelines, weather forecasting, predicting weather patterns, understanding nebulae in interstellar space, understanding large scale Geophysical fluid dynamics, geophysical flows involving oceans/atmosphere and Nuclear weapon design, modelling fission weapon detonation. Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
