171,048 research outputs found

    Do peaked solitary water waves indeed exist?

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    Many models of shallow water waves admit peaked solitary waves. However, it is an open question whether or not the widely accepted peaked solitary waves can be derived from the fully nonlinear wave equations. In this paper, a unified wave model (UWM) based on the symmetry and the fully nonlinear wave equations is put forward for progressive waves with permanent form in finite water depth. Different from traditional wave models, the flows described by the UWM are not necessarily irrotational at crest, so that it is more general. The unified wave model admits not only the traditional progressive waves with smooth crest, but also a new kind of solitary waves with peaked crest that include the famous peaked solitary waves given by the Camassa-Holm equation. Besides, it is proved that Kelvin's theorem still holds everywhere for the newly found peaked solitary waves. Thus, the UWM unifies, for the first time, both of the traditional smooth waves and the peaked solitary waves. In other words, the peaked solitary waves are consistent with the traditional smooth ones. So, in the frame of inviscid fluid, the peaked solitary waves are as acceptable and reasonable as the traditional smooth ones. It is found that the peaked solitary waves have some unusual and unique characteristics. First of all, they have a peaked crest with a discontinuous vertical velocity at crest. Especially, the phase speed of the peaked solitary waves has nothing to do with wave height. In addition, the kinetic energy of the peaked solitary waves either increases or almost keeps the same from free surface to bottom. All of these unusual properties show the novelty of the peaked solitary waves, although it is still an open question whether or not they are reasonable in physics if the viscosity of fluid and surface tension are considered.Comment: 53 pages, 13 figures, 7 tables. Accepted by Communications in Nonlinear Science and Numerical Simulatio

    Optimization of Renormalization Group Flow

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    Renormalization group flow equations for scalar lambda Phi^4 are generated using three classes of smooth smearing functions. Numerical results for the critical exponent nu in three dimensions are calculated by means of a truncated series expansion of the blocked potential. We demonstrate how the convergence of nu as a function of the order of truncation can be improved through a fine tuning of the smoothness of the smearing functions.Comment: 23 pages, 7 figure

    Finding the one-loop soliton solution of the short-pulse equation by means of the homotopy analysis method

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    The homotopy analysis method is applied to the short-pulse equation in order to find an analytic approximation to the known exact solitary upright-loop solution. It is demonstrated that the approximate solution agrees well with the exact solution. This provides further evidence that the homotopy analysis method is a powerful tool for finding excellent approximations to nonlinear solitary waves

    Statistical properties of solutions to the Navier-Stokes equation in the limit of vanishing viscosity

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    Presents a new approach to the Navier-Stokes turbulence. With the Gaussian soft constraint on the Navier-Stokes equation, the author derives the energy spectrum to be E(k) approximately k^-3 and k^-2 in two and three spatial dimensions respectively. The possible future developments are also pointed out

    Book Review: Understanding commercial Law

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    This article reviews the book: “Understanding commercial Law”, by Philippa Gerbic and Leigh Miller

    Hard Probe of Soft Matter Geometry and Fluctuations from RHIC to LHC

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    We report results on event-by-event hard probe of soft matter geometry and fluctuations in heavy ion collisions. Geometric data (v2v_2 of high ptp_t hadrons) from RHIC plus LHC clearly favors jet "monography" model with strong near-Tc enhancement of jet-medium interaction strength which also implies a less opaque medium at LHC. We also quantify the jet responses to all harmonic anisotropy vnv_n(n=1,2,3,4,5,6n=1,2,3,4,5,6) and their manifestation in hard-soft azimuthal correlations.Comment: 3 pages, 4 figures, contribution to CIPANP2012 Proceeding

    Dynamic Uplink/Downlink Resource Management in Flexible Duplex-Enabled Wireless Networks

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    Flexible duplex is proposed to adapt to the channel and traffic asymmetry for future wireless networks. In this paper, we propose two novel algorithms within the flexible duplex framework for joint uplink and downlink resource allocation in multi-cell scenario, named SAFP and RMDI, based on the awareness of interference coupling among wireless links. Numerical results show significant performance gain over the baseline system with fixed uplink/downlink resource configuration, and over the dynamic TDD scheme that independently adapts the configuration to time-varying traffic volume in each cell. The proposed algorithms achieve two-fold increase when compared with the baseline scheme, measured by the worst-case quality of service satisfaction level, under a low level of traffic asymmetry. The gain is more significant when the traffic is highly asymmetric, as it achieves three-fold increase.Comment: 7 pages, 7 figures, ICC 2017 Worksho
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