CLOSURE PROBLEM AND NUMERICAL STUDIES OF TURBULENCE.
Item
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Title
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CLOSURE PROBLEM AND NUMERICAL STUDIES OF TURBULENCE.
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Identifier
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AAI8423068
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identifier
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8423068
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Creator
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JIAN, QIAN.
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Contributor
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Chan Mou Tchen
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Date
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1984
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Language
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English
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Publisher
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City University of New York.
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Subject
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Engineering, Mechanical
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Abstract
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A variational approach is proposed to solve the closure problem of turbulence theory and to derive the Kolmogorov law in an Eulerian framework. Two convergent integral equations are obtained for two unknown functions. The Kolmogorov constant Ko is evaluated numerically, obtaining Ko = 1.2, which is compatible with the experimental data.;The initial-value problem of a forced Burgers equation is numerically solved by the Fourier expansion method. It is found that its solutions finally reach a steady state of 'laminar flow' which has no randomness and is stable to disturbances. Hence, strictly speaking, the so-called Burgers turbulence is not a turbulence. A new one-dimensional model of turbulence is proposed to simulate the Navier-Stokes turbulence. A series of numerical experiments on this one-dimensional turbulence are made and successful in obtaining Kolmogorov's k('-5/3) inertial-range spectrum. The (one-dimensional) Kolmogorov constant ranges from 0.5 to 0.65.;Finally the variational approach proposed in the first part of this research is applied to the new one-dimensional model of turbulence proposed in the second part. The Kolmogorov's inertial-range law is derived analytically, the corresponding theoretical (one-dimensional) Kolmogorov constant is 0.55, which is in good agreement with the results of the numerical experiments on the one-dimensional turbulence.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Engineering
