25,950 research outputs found
Linear Convergence of the Douglas-Rachford Method for Two Closed Sets
In this paper, we investigate the Douglas-Rachford method for two closed
(possibly nonconvex) sets in Euclidean spaces. We show that under certain
regularity conditions, the Douglas-Rachford method converges locally with
R-linear rate. In convex settings, we prove that the linear convergence is
global. Our study recovers recent results on the same topic
Computation of three-dimensional shock wave and boundary-layer interactions
Computations of the impingement of an oblique shock wave on a cylinder and a supersonic flow past a blunt fin mounted on a plate are used to study three dimensional shock wave and boundary layer interaction. In the impingement case, the problem of imposing a planar impinging shock as an outer boundary condition is discussed and the details of particle traces in windward and leeward symmetry planes and near the body surface are presented. In the blunt fin case, differences between two dimensional and three dimensional separation are discussed, and the existence of an unique high speed, low pressure region under the separated spiral vortex core is demonstrated. The accessibility of three dimensional separation is discussed
Development of relaxation turbulence models
Relaxation turbulence models have been intensively studied. The complete time dependent mass averaged Navier-Stokes equations have been solved for flow into a two dimensional compression corner. A new numerical scheme has been incorporated into the developed computed code with an attendant order of magnitude reduction in computation time. Computed solutions are compared with experimental measurements of Law for supersonic flow. Details of the relaxation process have been studied; several different relaxation models, including different relaxation processes and varying relaxation length, are tested and compared. Then a parametric study has been conducted in which both Reynolds number and wedge angle are varied. To assess effects of Reynolds number and wedge angle, the parametric study includes the comparison of computed separation location and upstream extent of pressure rise; numerical results are also compared with the measurements of surface pressure, skin friction and mean velocity field
Low-scale inflation in a model of dark energy and dark matter
We present a complete particle physics model that explains three major
problems of modern cosmology: inflation, dark matter and dark energy, and also
gives a mechanism for leptogenesis. The model has a new gauge group
that grows strong at a scale eV. We focus on the
inflationary aspects of the model. Inflation occurs with a Coleman-Weinberg
potential at a low scale, down to \sim 6\times 10^5\gev, being compatible
with observational data.Comment: 5 two-column pages, RevTex4; two reference added and minor changes
made in the text; published in JCA
Tangential Extremal Principles for Finite and Infinite Systems of Sets, I: Basic Theory
In this paper we develop new extremal principles in variational analysis that
deal with finite and infinite systems of convex and nonconvex sets. The results
obtained, unified under the name of tangential extremal principles, combine
primal and dual approaches to the study of variational systems being in fact
first extremal principles applied to infinite systems of sets. The first part
of the paper concerns the basic theory of tangential extremal principles while
the second part presents applications to problems of semi-infinite programming
and multiobjective optimization
Tangential Extremal Principles for Finite and Infinite Systems of Sets, II: Applications to Semi-infinite and Multiobjective Optimization
This paper contains selected applications of the new tangential extremal
principles and related results developed in Part I to calculus rules for
infinite intersections of sets and optimality conditions for problems of
semi-infinite programming and multiobjective optimization with countable
constraint
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