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2013, Mathematical Methods in the Applied Sciences
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11 pages
1 file
Communicated by T. Hishida Kato, Ponce, Beale and Majda prove the existence and uniqueness of maximal solution of Euler and Navier-Stokes equations and some blow-up criterion. In the periodic case, we establish that if the maximum time T is finite, then the growth of ku.t/k H m is at least of the order of .T t/ 2m=5 .
Communications in Mathematical Physics, 2012
We show that a necessary condition for T to be a potential blow up time is lim t↑T v(·, t) L 3 = ∞. 1991 Mathematical subject classification (Amer. Math. Soc.): 35K, 76D.
arXiv: Analysis of PDEs, 2021
A rigorous proof of no finite time blowup of the 3D Incompressible Navier Stokes equations in R 3 /T 3 is hereby shown as well as results on the velocity-pressure distribution. 1 Introduction The global regularity of the Navier-Stokes equations remains to be an outstanding unsolved problem in fluid mechanics. The Clay Institute is offering a significant prize for those who are successful in solving either one of four proposed problems, that is either a periodic or non-periodic regular or finite time blowup problem for the full 3D Navier Stokes equations.[1] The motivation behind the author's present contribution and work was to pursue the periodic Navier Stokes equations problem and it was shown by corresponding author [2](using Geometric Algebra) and then the authors in [3] (also see references contained therein) who confirmed in an applied setting that there is no finite time blowup for the special case of the theoretical class of solutions G being multiplicative between spatial variable y and coordinates (x, y, t). (see[2] and Eq.(13,15) of [3]) In addition the plots shown in [3] (Figure 1 there) were obtained for the special case of F (x, y) = 1 in [3](Eq13); Saddle surface generation and saddle orbits were obtained where the initial condition was a min-max type function with a min-max point at the center of a typical cube in the periodic Lattice of R 3 /T 3. This was plotted in [3] in Fig 1 (a,c) there. These saddle orbits indicate that there are instabilities leading to turbulence or possibly even STC. [4] Also the form of the solution obtained showed no finite time blowup. However the problem remained unsolved as to the general class of the form of solutions G due to the arbitrariness of the function itself. It is the purpose of the following article to provide a rigorous mathematical proof that G cannot be a blowup itself with respect to t except at a finite number of points in any given bounded subset of R 3 /T 3 if and only if in the initial data the energy is infinite. It is hypothesized that energy "cascades" from large-scale structures to smaller scale structures by an inertial and inviscid mechanism. This process does continue, and there is the creation of smaller and smaller structures which produce a hierarchy of eddies. It is inevitable that this process produces structures that are so small that molecular diffusion becomes important and viscous dissipation of energy eventually takes place. The scale at which this happens is the Kolmogorov length scale. [5] At these fine scales there is potential finite time blowup. This is also addressed above and beyond what was done in [2] and [3]. The issue of stability of solutions to the forced Navier-Stokes and damped Euler systems in periodic boxes has been studied in [6].There it is shown that for large, but fixed, Grashoff (Reynolds) number the turbulent behavior of all Leray-Hopf weak solutions of the three-dimensional Navier-Stokes equations, in a periodic box, is suppressed, when viewed in the right frame of reference, by large enough average flow of the initial data. In the present work there exists such a frame of reference in the z direction where the average flow of the initial data is arbitrarily large. For the form of solution G which is multiplicative, a unique time-periodic solution exists when the average flow of the initial data is large or a fast oscillating forcing term occurs, with no blowup. Here there is a suppression of turbulence. However for a general form of G, it is shown that there exists infinite type singularities on sets of measure zero corresponding to the centres of periodic cells of the
2012
Brezina, Jan. On asymptotic behavior of solutions to the compressible Navier-Stokes equation around a time-periodic parallel flow (Mathematical Analysis in Fluid and Gas Dynamics).
2015
In this paper we consider the Cauchy problem for the 3D Navier-Stokes equations for incompressible flows. The initial data are assumed to be smooth and rapidly decaying at infinity. A famous open problem is whether classical solutions can develop singularities in finite time. Assuming the maximum interval of existence to be finite, we give a unified discussion of various known solution properties as time approaches the blow-up time.
Boletim da Sociedade Paranaense de Matemática, 2016
In this paper we consider the Cauchy problem for the 3D navier-Stokes equations for incompressible flows. The initial data are assume d to be smooth and rapidly decaying at infinity. A famous open problem is whether classical solution can develop singularities in finite time. Assuming the maximal interval of existence to be finite, we give a unified discussion of various known solution properties as time approaches the blow-up time.
2021
A closely related problem to The Clay Math Institute "Navier-Stokes, breakdown of smooth solutions here on an arbitrary cube subset of three dimensional space with periodic boundary conditions is examined. The incompressible Navier-Stokes Equations are presented in a new and conventionally different way here, by naturally reducing them to an operator form which is then further analyzed. It is shown that a reduction to a general 2D N-S system decoupled from a 1D non-linear partial differential equation is possible to obtain. This is executed using integration over n-dimensional compact intervals which allows decoupling. Here we extract the measure-zero points in the domain where singularities may occur and are left with a pde that exhibits finite time singularity. The operator form is considered in a physical geometric vorticity case, and a more general case. In the general case, the solution is revealed to have smooth solutions which exhibit finite-time blowup on a fine measure zero set using the Poincaré and Gagliardo-Nirenberg inequalities and it is shown that for any non zero sufficiently large measure set in the form of cube subset of 3D there is no finite time blowup for the starred velocity for large dimension of cube and small δ. In particular vortices are shown to exist.
2019
This paper is devoted to proving the existence of time-periodic solutions of one-phase or two-phase problems for the Navier-Stokes equations with small periodic external forces when the reference domain is close to a ball. Since our problems are formulated in time-dependent unknown domains, the problems are reduced to quasiliner systems of parabolic equations with non-homogeneous boundary conditions or transmission conditions in fixed domains by using the so-called Hanzawa transform. We separate solutions into the stationary part and the oscillatory part. The linearized equations for the stationary part have eigen-value $0$, which is avoided by changing the equations with the help of the necessary conditions for the existence of solutions to the original problems. To treat the oscillatory part, we establish the maximal $L_p$-$L_q$ regularity theorem of the periodic solutions for the system of parabolic equations with non-homogeneous boundary conditions or transmission conditions, wh...
ZPE 223, 2022, 219ff.
Archaeometry, 2004
EDS, X-ray fluorescence, Raman spectroscopy, thermal expansion-shrinkage measurement and scanning electron microscopy were applied to determine the elemental components, structural phases and glazing temperatures of the transparent glazes, blue underglaze and overglaze tam thai (including gold-like lustre) decorations from the 15th-century Vietnamese porcelains/stonewares found at the Chu Î âu-My Xa kiln site and in the Cù Lao Chàm (Hôi An) cargo. The ancient technology for colouring the glazes is discussed. The various blue tones in the underglazed décor result from cobalt-containing manganese ore, with the intentional addition of iron oxide. The overglaze copper-green and the gold-like lustre were obtained by dispersing copper in lead-based glass. The red colour was made using hematite dispersed in lead-rich flux.
Leisure is most basically defined as "the time free from work". The ancient conception and forms of leisure were quite different from the modern ones, which came into discussion during the industrial era. The Roman society was highly stratified and comprised of diverse social classes for which leisure acquired different forms and meanings. Every stratum of the Roman society enjoyed the possibilities and pleasures of leisure proportional to its hierarchy in the social system, so that leisure can be investigated in both public and private contexts in the Roman world. This study aims to investigate "leisure", which was one of the main driving social forces in the Roman society, in spatial terms with reference to Roman domestic architecture. The study focuses on central Italy and particularly on Ephesus, the latter of which is a good example to discuss how the Roman conception of leisure was spatially materialized in a provincial private setting since a group of well studied, documented, and published houses constitute an appropriate comparative sample and context in Ephesus. The spatial organization and characteristics of the spaces housing leisurely activities are discussed on the basis of an "axes-scheme" that regulated and even dictated the visual and bodily interaction of the participants with certain spaces and elements during leisure activities either in a static state (sitting, reclining), or a kinetic one (walking, perambulating). The "visual axes" are those perceived in either of these states, along which the eye is directed towards a visual focal point, whereas the "dynamic axes" are those along which people move during a kinetic leisurely activity. The location, architecture, and use of leisure-oriented spaces in the Roman period houses in Ephesus, such as triclinium, exedra, oecus, museion, and peristyle courtyard are examined with reference to the proposed axes-scheme to present and compare the operation of leisure in the Roman provincial and private setting.
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