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1.
This paper reports a combined experimental and numerical investigation of three-dimensional steady turbulent flows in inlet manifolds of square cross-section. Predictions and measurements of the flows were carried out using computational fluid dynamics and laser Doppler anemometry techniques respectively. The flow structure was characterized in detail and the effects of flow split ratio and inlet flow rate were studied. These were found to cause significant variations in the size and shape of recirculation regions in the branches, and in the turbulence levels. It was then found that there is a significant difference between the flow rates through different branches. The performance of the code was assessed through a comparison between predictions and measurements. The comparison demonstrates that all important features of the flow are well represented by the predictions. 相似文献
2.
Elmar Schrohe 《Annals of Global Analysis and Geometry》1996,14(4):403-425
Let B be a manifold with conical singularities, and denote by the smooth bounded manifold with cylindrical ends obtained by blowing up near the singularities.B.-W. Schulze has developed a framework for a pseudodifferential calculus on B by defining various classes of distribution spaces and operator algebras, working in fixed coordinates on the manifold . I am showing here that the Mellin Sobolev spaces without asymptotics, the cone algebra without asymptotics, and its ideal of smoothing operators are independent of the choice of coordinates and therefore may be considered intrinsic objects for manifolds with conical singularities. 相似文献
3.
We study the structure and asymptotic behavior of the resolvent of elliptic cone pseudodifferential operators acting on weighted
Sobolev spaces over a compact manifold with boundary. We obtain an asymptotic expansion of the resolvent as the spectral parameter
tends to infinity, and use it to derive corresponding heat trace and zeta function expansions as well as an analytic index
formula.
相似文献
4.
A Theoretical and Computational Framework for Isometry Invariant Recognition of Point Cloud Data 总被引:1,自引:0,他引:1
Point clouds are one of the most primitive and fundamental manifold
representations. Popular sources of point clouds are three-dimensional
shape acquisition devices such as laser range scanners. Another
important field where point clouds are found is in the representation
of high-dimensional manifolds by samples. With the increasing
popularity and very broad applications of this source
of data, it is natural and important to work directly with this
representation, without having to go through the intermediate and
sometimes impossible and distorting steps of surface reconstruction.
A geometric framework for comparing manifolds given by point clouds
is presented in this paper. The underlying theory is based on
Gromov-Hausdorff distances, leading to isometry invariant and
completely geometric comparisons. This theory is embedded in a
probabilistic setting as derived from random sampling of manifolds,
and then combined with results on matrices of pairwise geodesic distances
to lead to a computational implementation of the framework. The theoretical and
computational results presented here are complemented with
experiments for real three-dimensional shapes. 相似文献
5.
In this work we focus on the efficient representation and computation of the eigenvalues and eigenfunctions of the surface Schrödinger operator that governs a class of nonlinear Ginzburg–Landau (GL) superconductivity models on rotationally symmetric Riemannian 2-manifolds S. We identify and analyze a complete orthonormal system in of eigenmodes having a variable-separated form. For the unknown functions in this ansatz, our analysis facilitates the identification of approximate spectral problems whose eigenvalues lie arbitrarily near corresponding eigenvalues of the Schrödinger operator. We then develop and implement an arbitrary order finite element method for the efficient numerical approximation of the eigenvalue problem. We also demonstrate our analysis, algorithm and its convergence rate using parallel computations performed on a variety of choices of smooth and non-smooth surfaces S. 相似文献
6.
Manuel Amann 《Topology and its Applications》2011,158(2):183-189
Positive Quaternion Kähler Manifolds are Riemannian manifolds with holonomy contained in Sp(n)Sp(1) and with positive scalar curvature. Conjecturally, they are symmetric spaces. In this article we are mainly concerned with Positive Quaternion Kähler Manifolds M satisfying b4(M)=1. Generalising a result of Galicki and Salamon we prove that M4n in this case is homothetic to a quaternionic projective space if 2≠n?6. 相似文献
7.
8.
Thomas Krainer 《偏微分方程通讯》2013,38(2):257-315
We prove the existence of sectors of minimal growth for realizations of boundary value problems on conic manifolds under natural ellipticity conditions. Special attention is devoted to the clarification of the analytic structure of the resolvent. 相似文献
9.
V. S. Anishchenko A. S. Kopeikin J. Kurths T. E. Vadivasova G. I. Strelkova 《Physics letters. A》2000,270(6):301-307
On the basis of method [1] proposed for diagnosing 2-dimensional chaotic saddles we present a numerical procedure to distinguish hyperbolic and nonhyperbolic chaotic attractors in three-dimensional flow systems. This technique is based on calculating the angles between stable and unstable manifolds along a chaotic trajectory in R3. We show for three-dimensional flow systems that this serves as an efficient characteristic for exploring chaotic differential systems. We also analyze the effect of noise on the structure of angle distribution for both 2-dimensional invertible maps and a 3-dimensional continuous system. 相似文献
10.
Thomas Schick 《Mathematische Nachrichten》2001,223(1):103-120
For non–compact manifolds with boundary we prove that bounded geometry defined by coordinate–free curvature bounds is equivalent to bounded geometry defined using bounds on the metric tensor in geodesic coordinates. We produce a nice atlas with subordinate partition of unity on manifolds with boundary of bounded geometry and we study the change of geodesic coordinate maps. 相似文献