13,458 research outputs found

    Forward Drell-Yan plus backward jet as a test of BFKL evolution

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    We study Drell-Yan plus jet events where the gauge boson is produced in the forward direction of one of the colliding protons and a jet is produced in the forward direction of the second proton. The resulting large rapidity difference between the final states then opens up the phase space for BFKL evolution. First numerical results on partonic level are provided.Comment: 4 pages, 2 figures, proceedings of the XX Workshop on Deep-Inelastic Scattering and Related Subjects, 26-30 March, University of Bonn (2012

    Local stability analysis for a planar shock wave

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    A procedure to study the local stability of planar shock waves is presented. The procedure is applied to a Rankine-Hugoniot shock in a divergent/convergent nozzle, to an isentropic shock in a divergent/convergent nozzle, and to Rankine-Hugoniot shocks attached to wedges and cones. It is shown that for each case, the equation governing the shock motion is equivalent to the damped harmonic oscillator equation

    Three-dimensional simulation of vortex breakdown

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    The integral form of the complete, unsteady, compressible, three-dimensional Navier-Stokes equations in the conservation form, cast in generalized coordinate system, are solved, numerically, to simulate the vortex breakdown phenomenon. The inviscid fluxes are discretized using Roe's upwind-biased flux-difference splitting scheme and the viscous fluxes are discretized using central differencing. Time integration is performed using a backward Euler ADI (alternating direction implicit) scheme. A full approximation multigrid is used to accelerate the convergence to steady state

    Using the BFKL resummation to fit DIS data: collinear and running coupling effects

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    The proton structure function F2 is studied in the low x regime using BFKL evolution. The next to leading logarithmic (NLL) analysis requires the inclusion of running coupling effects which lead to off-diagonal terms in the evolution kernel. An all-orders resummation is used to improve the collinear behavior of the NLL BFKL result. We emphasize the theoretical uncertainties that appear throughout the analysis and give a comparison to the combined HERA data.Comment: 4 pages, 5 figures, proceedings of the XX Workshop on Deep-Inelastic Scattering and Related Subjects, 26-30 March, University of Bonn (2012

    Development of a computer code for calculating the steady super/hypersonic inviscid flow around real configurations. Volume 1: Computational technique

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    A numerical procedure has been developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second order accurate finite difference scheme is used to integrate the three dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool
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