Download or read book A Semi spectral Numerical Method for Modeling the Vorticity Dynamics of the Near core Region of Hurricane like Vortices written by Michael T. Montgomery and published by . This book was released on 2000 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of Concentrated Vortices written by S. V. Alekseenko and published by Springer Science & Business Media. This book was released on 2007-08-29 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents comprehensive and authoritative coverage of the wide field of concentrated vortices observed in nature and technique. The methods for research of their kinematics and dynamics are considered. Special attention is paid to the flows with helical symmetry. The authors have described models of vortex structures used for interpretation of experimental data which serve as a ground for development of theoretical and numerical approaches to vortex investigation.
Download or read book Intense Atmospheric Vortices written by L. Bengtsson and published by Springer. This book was released on 1982-08 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concept of vorticity is of central importance in fluid mechanics and the change and variability of atmospheric flow is dominated by transient vortices of different time and space scales. Of particular importance are the most in tense vortices such as hurricanes, typhoons and tornadoes which are associated with extreme and hazardous weather events of great concern to society. In recent years the un derstanding of these phenomena has grown due to increased and improved surveillance by satellites and aircraft as well as by numerical modelling and simulation, theoretical studies and laboratory experiments. The symposium on "Intense Atmospheric Vortices" was held at the European Centre for Medium Range Weather Forecasts (ECMWF), Reading, England, July 14-17, 1981. The subject area of the Symposium was concerned with observational work, experimental models, theoretical and numerical studies in volving hurricanes, typhoons, tornadoes and related pheno mena. The aim was to bring together experts on these meteo rological processes and on the fundamental fluid-dynamic mechanisms for vorticity intensification from all parts of the world. Thirtyfour scientists participated in the Sympo sium, including more than half of those leading world ex perts in the field whom the organizers had invited.
Download or read book Vorticity Dynamics in the Presence of Shallow Water Waves written by Joe D. Geiman and published by ProQuest. This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a theoretical and numerical investigation of the interaction of a circular Rankine vortex and a surface gravity wavefield with length and time scales applicable to surfzone vortices. An approximate solution first given by Coste et al. [11] using a wave equation that accounts for the Doppler shift and diffraction by the vortical current is presented. Here, we calculate time-averaged wave quantities such as the radiation stress and wave momentum as a function of the vortex circulation. The Craik-Leibovich [12] wave-mean flow interaction equations predict a net drift of the vortex in the direction of the refracted waves at the core, with a velocity on the order of the Stokes drift. The approximate analytical wave solution agrees well with the numerical results from the parabolic wave model REF-DIF as well as the fully nonlinear wave model, FUNWAVE. Differences in FUNWAVE are primarily due to the steepening (and speeding up) of the wave near the vortex core. The results of a full numerical simulation of the combined wave-current interaction in a rectangular domain and flat bottom with a wave absorbing layer at the domain boundary are given. Here it is shown that the dynamics of the vortex consists of steady translation in the upwave direction due to an 'anti-Stokes drift', deformation and rotation from wave-induced flows near the core as well as shear-type vorticity filaments that wind around the vortex boundary as seen in Melander et al. [37]. This is compared to a vortex subjected to random velocity perturbation in the absence of waves.
Download or read book Dynamics of Vortex Structures in a Stratified Rotating Fluid written by Mikhail A. Sokolovskiy and published by Springer Science & Business Media. This book was released on 2013-08-28 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an extensive analysis of the dynamics of discrete and distributed baroclinic vortices in a multi-layer fluid that characterizes the main features of the large and mesoscales dynamics of the atmosphere and the ocean. It widely covers the case of hetonic situations as well as the case of intrathermocline vortices that are familiar in oceanographic and of recognized importance for heat and mass transfers. Extensive typology of such baroclinic eddies is made and analysed with the help of theoretical development and numerical computations. As a whole it gives an overview and synthesis of all the many situations that can be encountered based on the long history of the theory of vortex motion and on many new situations. It gives a renewed insight on the extraordinary richness of vortex dynamics and open the way for new theoretical, observational and experimental advances. This volume is of interest to experts in physical oceanography, meteorology, hydrodynamics, dynamic systems, involved in theoretical, experimental and applied research and lecturers, post-graduate students, and students in these fields.
Download or read book A Numerical Study of Viscous Vortex Rings Using a Spectral Method written by Sharon K. Stanaway and published by . This book was released on 1988 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Dynamics Statistical Mechanics and Planetary Atmospheres written by Chjan C. Lim and published by World Scientific. This book was released on 2009 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study introduces the reader with a background in either fluid mechanics or statistical mechanics to the modeling of planetary atmospheres by barotropic and shallow-water models. These potent models are introduced in both analytical and numerical treatments highlighting the ways both approaches inform and enlighten the other.
Download or read book Numerical Experiments on Vortex Dynamics written by Ireneusz Zawadzki and published by . This book was released on 1989 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultrafast Vortex Core Dynamics Investigated by Finite element Micromagnetic Simulations written by Sebastian Gliga and published by Forschungszentrum Jülich. This book was released on 2010 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical Aspects of Vortex Dynamics written by Russel E. Caflisch and published by SIAM. This book was released on 1989-01-01 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Procedure for Numerical Integration of the Spectral Vorticity Equation written by Ferdinand Baer and published by . This book was released on 1960 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Dominated Flows written by Lu Ting and published by Springer Science & Business Media. This book was released on 2007-07-05 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph provides in-depth analyses of vortex dominated flows via matched and multiscale asymptotics, and demonstrates how insight gained through these analyses can be exploited in the construction of robust, efficient, and accurate numerical techniques. The book explores the dynamics of slender vortex filaments in detail, including fundamental derivations, compressible core structure, weakly non-linear limit regimes, and associated numerical methods. Similarly, the volume covers asymptotic analysis and computational techniques for weakly compressible flows involving vortex-generated sound and thermoacoustics. The book is addressed to both graduate students and researchers.
Download or read book Coarse grained Simulations of Vortex Dynamics and Transition in Complex High Re Flows written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent flow complexity in applications in engineering, geophysics and astrophysics typically requires achieving accurate and dependable large scale predictions of highly nonlinear processes with under-resolved computer simulation models. Laboratory observations typically demonstrate the end outcome of complex non-linear three-dimensional physical processes with many unexplained details and mechanisms. Carefully controlled computational experiments based on the numerical solution of the conservation equations for mass, momentum, and energy, provide insights into the underlying flow dynamics. Relevant computational fluid dynamics issues to be addressed relate to the modeling of the unresolved tlow conditions at the subgrid scale (SGS) level - within a computational cell, and at the supergrid (SPG) scale - at initialization and beyond computational boundaries. SGS and SPG information must be prescribed for closure of the equations solved numerically. SGS models appear explicitly or implicitly as additional source tenns in the modified flow equations solved by the numerical solutions being calculated, while SPG models provide the necessary set of initial and boundary conditions that must be prescribed to ensure unique well-posed solutions. From this perspective, it is clear that the simulation process is inherently determined by the SGS and SPG information prescription process. On the other hand, observables in laboratory experiments are always characterized by the finite scales of the instrumental resolution of measuring/visualizing devices, and subject as well to SPG issues. It is thus important to recognize the inherently intrusive nature of observations based on numerical or laboratory experiments. Ultimately, verification and validation (V & V) frameworks and appropriate metrics for the specific problems at hand are needed to establish predictability of the simulation model. Direct numerical simulation (DNS) - resolving all relevant space/time scales, is prohibitively expensive in the foreseeable future for most practical flows of interest at moderate-to-high Reynolds number R. On the other end of the simulation spectrum are the Reynolds-Averaged Navier-Stokes (RANS) approaches - which model the turbulent effects. In the coarsegrained large eddy simulation (LES) strategies, the large energy containing structures are resolved, the smaller structures are filtered out, and unresolved SGS effects are modeled. By necessity - rather than choice, LES effectively becomes the intermediate approach between DNS and RANS. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a particular LES denoted implicit LES (ILES), using the class of nonoscillatory finite-volume (NFV) numerical algorithms. Use of the modified equation as framework for theoretical analysis, demonstrates that leading truncation tenns associated with NFV methods provide implicit SGS models of mixed anisotropic type and regularized motion of discrete observables. Tests in fundamental applications ranging from canonical to very complex flows indicate that ILES is competitive with conventional LES in the LES realm proper - flows driven by large scale features. High-Re flows are vortex dominated and governed by short convective timescales compared to those of diffusion, and kinematically characterized at the smallest scales by slender worm vortices with insignificant internal structure. This motivates nominally inviscid ILES methods capable of capturing the high-Re dissipation dynamics and of handling vortices as shocks in shock capturing schemes. Depending on flow regimes, initial conditions, and resolution, additional modeling may be needed to emulate SGS driven physics, such as backscatter, chemical reaction, material mixing, and near-wall flow-dynamics - where typically-intertwined SGS/SPG issues need to be addressed. A major research focus is recognizing when additional explicit models and/or numerical treatments are needed and ensuring that mixed explicit and implicit SGS models can effectively act in collaborative rather than interfering fashion. We survey our present understanding of the theoretical basis of lLES, including connections with the classical LES and finite-scale dynamics perspectives. Examples from recent lLES studies are presented, including canonical turbulence test cases and shock driven turbulence; relevant V & V issues are demonstrated in this context.
Download or read book Vortex Boundary Layer Dynamics written by Timothy Lee Wilson and published by . This book was released on 1981 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of High order Vorticity Confinement Schemes written by Ilias Petropoulos and published by . This book was released on 2018 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortices are flow structures of primary interest in a wide range of fluid dynamics applications including wakes, fluid-structure interaction, flow separation and turbulence. Albeit their importance, standard Computational Fluid Dynamics (CFD) methods very often fail to provide an accurate representation of vortices. This is primarily related to the schemes' numerical dissipation which, if inadequately tuned for the calculation of vortical flows, results in the artificial spreading and diffusion of vortices in numerical simulations. Among other approaches, the Vorticity Confinement (VC) method of J. Steinhoff allows balancing the baseline dissipation within vortices by introducing non-linear anti-dissipation in the discretization of the flow equations, but remains at most first-order accurate. At the same time, remarkable progress has recently been made on the development of high-order numerical methods. These allow reducing the problem of excess dissipation, but the diffusion of vortices remains important for many applications. The present study aims at developing high-order extensions of the VC method to reduce the excess dissipation of vortices, while preserving the accuracy of high-order methods. First, the schemes are analyzed in the case of the linear transport equation, based on time-space coupled and uncoupled formulations. A spectral analysis of nonlinear schemes with VC is performed analytically and numerically, due to their nonlinear character. These schemes exhibit improved dispersive and dissipative properties compared to their linear counterparts at all orders of accuracy. In a second step, third- and fifth-order accurate VC schemes are developed for the compressible Navier-Stokes equations. These remain conservative, rotationally invariant and independent of the baseline scheme, as the original VC2 formulation. Numerical tests validate the increased order of accuracy and the capability of high-order VC extensions to balance dissipation within vortices. Finally, schemes with VC are applied to the calculation of turbulent flows, in an implicit Large Eddy Simulation (ILES) approach. In these applications, numerical schemes with VC exhibit improved resolvability compared to their baseline linear version, while they are capable of producing consistent results even in complex vortical flows.
Download or read book The Analytical Dynamics of the Spectral Vorticity Equation written by George W. Platzman and published by . This book was released on 1962 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Viscous Vortical Flows written by Lu Ting and published by Springer. This book was released on 2014-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive account of the asymptotic theory of slender vortices with diffusion cores. Addressed to both graduate students and researchers it describes the mathematical model and its numerical analysis. The asymptotic analysis involves two length and two time scales. Consistency conditions and time invariance of moments of vorticity are given and applied to numerical solutions. The authors also describe consistency conditions between the large circumferential and axial velocity in the core.
