共查询到12条相似文献，搜索用时 43 毫秒
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Song Fu 《中国科学A辑(英文版)》1998,41(6):638-646
The theoretical foundation for the modelling of the turbulent pressure-strain correlations in rotating reference frame is
presented. Based on the recently developed materially-frame indifference principle it is observed that most of the existing
second-moment closures violate the Taylor-Proudman theorem in the limit of rapid rotation. It is shown that the application
of the materially-frame indifference principle gives rise to the formation of a new pressure-strain correlation model which
satisfies the Taylor-Proudman theorem.
Project supported by thr National Natural Science Foundation of China (Grant No. 19421003), the State Education Commission
and Tsinghua University. 相似文献
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对一个不等式的一点注记 总被引：2，自引：0，他引：2
刘证 《纯粹数学与应用数学》2001,17(4):349-351
讨论了不等式bx+y-ax+y/bx-ax≥x+y/x(ab)r/2及其逆成立或不成立的一切情形,其中x,y∈R x≠0 a,b＞0,a≠b. 相似文献
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Zhukovskaya L. V. Savchenko A. M. Sadovnikova M. B. 《Theoretical and Mathematical Physics》2004,138(1):118-122
We find the spin oscillation branch with the frequency =(H/)(k/k
c)2 in the paramagnetic phase for systems with exchange interaction in the presence of an external magnetic field
. 相似文献
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JianQuan Ge 《中国科学A辑(英文版)》2008,51(6):1127-1134
By using moving frame theory,first we introduce 2p-th mean curvatures and(2p 1)-th mean curvature vector fields for a submanifold.We then give an integral expression of them that characterizes them as mean values of symmetric functions of principle curvatures.Next we apply it to derive directly the celebrated Weyl-Gray tube formula in terms of integrals of the 2p-th mean curvatures and some Minkowski-type integral formulas. 相似文献
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We investigate some geometric properties of the curl operator, based on its diagonalization and its expression as a non-local symmetry of the pseudo-derivative $(−Delta)^{1/2}$ among divergence-free vector fields with finite energy. In this context, we introduce the notion of spin-definite fields, i.e. eigenvectors of $(−Delta)^{−1/2}$ curl. The two spin-definite components of a general 3D incompressible flow untangle the right-handed motion from the left-handed one. Having observed that the non-linearity of Navier-Stokes has the structure of a cross-product and its weak (distributional) form is a determinant that involves the vorticity, the velocity and a test function, we revisit the conservation of energy and the balance of helicity in a geometrical fashion. We show that in the case of a finite-time blow-up, both spin-definite components of the flow will explode simultaneously and with equal rates, i.e. singularities in 3D are the result of a conflict of spin, which is impossible in the poorer geometry of 2D flows. We investigate the role of the local and non-local determinants $$int_0^Tint_{mathbb{R}^3}{rm det}({rm curl}u,u,(-Delta)^{theta}u)$$ and their spin-definite counterparts, which drive the enstrophy and, more generally, are responsible for the regularity of the flow and the emergence of singularities or quasi-singularities. As such, they are at the core of turbulence phenomena. 相似文献
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Hani Ali 《Applicable analysis》2013,92(2):339-355
We study a regularization of the rotational Navier–Stokes equations that we call the Rotational Approximate Deconvolution Model (RADM). We generalize the deconvolution model, studied by Berselli and Lewandowski in (Convergence of Approximate Deconvolution Models to the mean Navier- Stokes equations. Annales de l’Institut Henri Poincare (C), NonLinear Analysis. 2012;29:171–198), to the RADM with fractional regularization, where the convergence of the solution is studied with weaker conditions on the parameter regularization. 相似文献
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Nonnegative tensor decomposition allows us to analyze data in their ‘native’ form and to present results in the form of the sum of rank-1 tensors that does not nullify any parts of the factors. In this paper, we propose the geometrical structure of a basis vector frame for sum-of-rank-1 type decomposition of real-valued nonnegative tensors. The decomposition we propose reinterprets the orthogonality property of the singularvectors of matrices as a geometric constraint on the rank-1 matrix bases which leads to a geometrically constrained singularvector frame. Relaxing the orthogonality requirement, we developed a set of structured-bases that can be utilized to decompose any tensor into a similar constrained sum-of-rank-1 decomposition. The proposed approach is essentially a reparametrization and gives us an upper bound of the rank for tensors. At first, we describe the general case of tensor decomposition and then extend it to its nonnegative form. At the end of this paper, we show numerical results which conform to the proposed tensor model and utilize it for nonnegative data decomposition. 相似文献
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-convex functionsIn this paper, the inequalities for the weighted mean of -convex functions are established. As applications, inequalities between the two-parameter mean of an -convex function and extended mean values are given.