Download or read book Point Particle Model for Disperse Turbulent Flows written by and published by . This book was released on 2009 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particles in Turbulent Flows written by Leonid I. Zaichik and published by John Wiley & Sons. This book was released on 2008-12-04 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only work available to treat the theory of turbulent flow with suspended particles, this book also includes a section on simulation methods, comparing the model results obtained with the PDF method to those obtained with other techniques, such as DNS, LES and RANS. Written by experienced scientists with background in oil and gas processing, this book is applicable to a wide range of industries -- from the petrol industry and industrial chemistry to food and water processing.

Download or read book Particles in Wall Bounded Turbulent Flows Deposition Re Suspension and Agglomeration written by Jean-Pierre Minier and published by Springer. This book was released on 2016-07-26 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents an up-to-date review of turbulent two-phase flows with the dispersed phase, with an emphasis on the dynamics in the near-wall region. New insights to the flow physics are provided by direct numerical simuation and by fine experimental techniques. Also included are models of particle dynamics in wall-bounded turbulent flows, and a description of particle surface interactions including muti-layer deposition and re-suspension.

Download or read book Modeling Approaches and Computational Methods for Particle laden Turbulent Flows written by Shankar Subramaniam and published by Academic Press. This book was released on 2022-10-20 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling Approaches and Computational Methods for Particle-laden Turbulent Flows introduces the principal phenomena observed in applications where turbulence in particle-laden flow is encountered while also analyzing the main methods for analyzing numerically. The book takes a practical approach, providing advice on how to select and apply the correct model or tool by drawing on the latest research. Sections provide scales of particle-laden turbulence and the principal analytical frameworks and computational approaches used to simulate particles in turbulent flow. Each chapter opens with a section on fundamental concepts and theory before describing the applications of the modelling approach or numerical method. Featuring explanations of key concepts, definitions, and fundamental physics and equations, as well as recent research advances and detailed simulation methods, this book is the ideal starting point for students new to this subject, as well as an essential reference for experienced researchers. Provides a comprehensive introduction to the phenomena of particle laden turbulent flow Explains a wide range of numerical methods, including Eulerian-Eulerian, Eulerian-Lagrange, and volume-filtered computation Describes a wide range of innovative applications of these models

Download or read book Turbulent Particle Laden Gas Flows written by Aleksei Y. Varaksin and published by Springer Science & Business Media. This book was released on 2007-07-05 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents results of experimental and theoretical studies of "gas-solid particles" turbulent two-phase flows. It analyzes the characteristics of heterogeneous flows in channels (pipes), as well as those in the vicinity of the critical points of bodies subjected to flow and in the boundary layer developing on their surface. Coverage also treats in detail problems of physical simulation of turbulent gas flows which carry solid particles.

Download or read book Collective Dynamics of Particles written by Cristian Marchioli and published by Springer. This book was released on 2017-02-21 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book surveys the state-of-the-art methods that are currently available to model and simulate the presence of rigid particles in a fluid flow. For particles that are very small relative to the characteristic flow scales and move without interaction with other particles, effective equations of motion for particle tracking are formulated and applied (e.g. in gas-solid flows). For larger particles, for particles in liquid-solid flows and for particles that interact with each other or possibly modify the overall flow detailed model are presented. Special attention is given to the description of the approximate force coupling method (FCM) as a more general treatment for small particles, and derivations in the context of low Reynolds numbers for the particle motion as well as application at finite Reynolds numbers are provided. Other topics discussed in the book are the relation to higher resolution immersed boundary methods, possible extensions to non-spherical particles and examples of applications of such methods to dispersed multiphase flows.

Download or read book Subgrid scale Modeling and Wavelet Analysis for Preferential Concentration of Inertial Point Particles in Turbulent Flows written by Maxime Bassenne and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A striking feature of particle-laden turbulent flows is the presence of particle clouds that result from the tendency of inertial particles to preferentially sample specific regions of the flow field. This phenomenon is central to a number of important physical processes. However, computational predictions of preferential concentration at high Reynolds numbers are challenging, since the numerical resolution of the participating scales is typically unaffordable. This dissertation contributes both to the analysis of the preferential concentration phenomenon and the development of subgrid-scale models for the prediction of preferential concentration in large-eddy simulations of particle-laden turbulence. First, direct numerical simulations of incompressible homogeneous-isotropic turbulence laden with a dilute suspension of inertial point particles are performed in conjunction with a wavelet multi-resolution analysis of the results. The use of spatially localized wavelet basis functions enables the simultaneous consideration of physical and scale spaces in the spectral characterization of the flow field of the carrier phase and the concentration field of the disperse phase. The multi-resolution analysis of the disperse phase provides statistical information about the spatial variability of a scale-dependent coarse-grained number density field and the local energy spectra of its fluctuations, characterizing the sensitivities of those quantities to variations in scale and Stokes number. In particular, the spatial variabilities of the wavelet energy spectrum of the particle concentration fluctuations are observed to be maximum in regimes where the particles preferentially concentrate. The results highlight the scale-dependent inhomogeneities of the structures in the concentration field generated by preferential concentration, and the existence of characteristic scales of interaction between the disperse and carrier phases. Additionally, an inter-phase multi-resolution analysis is performed that indicates the occurrence of a spatial anti-correlation between the enstrophy and kinetic-energy spectra of the carrier phase and the particle concentration at small scales in regimes where preferential concentration is important. This anti-correlation vanishes as the scale is increased, and is largely suppressed when the preferential-concentration effect is negligible. Secondly, a wavelet-based method for extraction of clusters of inertial particles in turbulent flows is presented that is based on decomposing Eulerian particle number-density fields into the sum of a coherent (organized) and an incoherent (disorganized) components. The coherent component is associated with the clusters and is extracted by filtering the wavelet-transformed particle number-density field based on an energy threshold. The analysis shows that in regimes where the preferential concentration is important, the coherent component representing the clusters can be described by just 1.6% of the total number of wavelet coefficients, thereby illustrating the sparsity of the particle number-density field. On the other hand, the incoherent portion is visually structureless and much less correlated that the coherent one. An application of the method is illustrated in the form of a grid-adaptation algorithm that results in non-uniform meshes with fine and coarse elements near and away from particle clusters, respectively. In regimes where preferential concentration in clusters is important, the grid adaptation leads to a reduction of the number of control volumes by one to two orders of magnitude. Thirdly, two dynamic models for turbulent velocity fluctuations are proposed for large-eddy simulations of dispersed multiphase flows. The first model is simple, involves no significant computational overhead, contains no adjustable parameters, and is flexible enough to be deployed in any type of flow solvers and grids, including unstructured setups. The approach is based on the use of elliptic differential filters to model the subgrid-scale velocity. The only model parameter, which is related to the nominal filter width, is determined dynamically by imposing consistency constraints on the estimated subgrid energetics. The second model constructs a velocity that contains scales smaller than the coarse-grid resolution, thereby enabling the prediction of small-scale phenomena such as the preferential concentration of particles in high-strain regions. The construction of the spectrally enriched velocity field in physical space is made dynamically, and is based on 1) modeling the smallest resolved eddies of sizes comparable to the grid size via approximate deconvolution, and 2) reconstructing the subgrid-scale fluctuations via non-linear generation of small-scale turbulence. The model does not contain tunable parameters, can be deployed in non-uniform grids, and is applicable to inhomogeneous flows subject to arbitrary boundary conditions. The performance of both models is tested in large-eddy simulations of homogeneous-isotropic turbulence laden with particles, where improved agreement with direct numerical simulation results is obtained for the statistics of preferential concentration. Lastly, application to wall-modeled large-eddy simulations of particle-laden channel flow is presented. Results of the application of existing wall models to particle-laden turbulent channel flows are described, and prospective pathways for improving their performance are suggested. The focus is on the prediction of the spatial distribution statistics of the disperse phase. It is observed that wall-modeled large-eddy simulations without particular treatment for the particles in the wall-adjacent cells overpredict the near-wall accumulation of particles. The choice of the continuous representation of the velocity field between the first grid point and the wall is shown to be of primary importance. A wall-modeling strategy is explored that performs well at large Stokes numbers. It relies on using interpolation kernels near the wall that mimic the law of the wall for the wall-parallel velocity, and direct numerical simulation profiles of the fluctuations for the wall-perpendicular velocity. Applications of the two developed subgrid-scale models are shown to improve the prediction of preferential concentration, but have no effect on the mean concentration profile.

Download or read book Theory and Modeling of Dispersed Multiphase Turbulent Reacting Flows written by Lixing Zhou and published by Butterworth-Heinemann. This book was released on 2018-01-25 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory and Modeling of Dispersed Multiphase Turbulent Reacting Flows gives a systematic account of the fundamentals of multiphase flows, turbulent flows and combustion theory. It presents the latest advances of models and theories in the field of dispersed multiphase turbulent reacting flow, covering basic equations of multiphase turbulent reacting flows, modeling of turbulent flows, modeling of multiphase turbulent flows, modeling of turbulent combusting flows, and numerical methods for simulation of multiphase turbulent reacting flows, etc. The book is ideal for graduated students, researchers and engineers in many disciplines in power and mechanical engineering. Provides a combination of multiphase fluid dynamics, turbulence theory and combustion theory Covers physical phenomena, numerical modeling theory and methods, and their applications Presents applications in a wide range of engineering facilities, such as utility and industrial furnaces, gas-turbine and rocket engines, internal combustion engines, chemical reactors, and cyclone separators, etc.

Download or read book Computational Fluid Dynamics for the Petrochemical Process Industry written by R.V.A. Oliemans and published by Springer. This book was released on 2012-11-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second of the 1989 conferences in the Shell Conference Series, held from 10 to 12 December in the Netherlands and organized by Koninklijke/Shell-Laboratorium, Amsterdam, was on "Computational Fluid Dynamics for Petrochemical Process Equip ment". The objective was to generate a shared perspective on the subject with respect to its role in the design of equipment involving complex flows. The conference was attended by scientists from four Shell laboratories and experts from universities in the USA, France, Great Britain, Germany and The Netherlands. R. V. A. Oliemans, G. Ooms and T. M. M. Verheggen formed the organizing committee. Complexities in fluid flow may arise from equipment geometry and/or the fluids themselves, which can be mUlti-component, single-phase or multiphase. Pressure and temperature gradients and any reactivity of components in the flow stream can be additional factors. Four themes were addressed: turbulent reacting and non-reacting flow, dispersed multiphase flow, separated two-phase flow and fluid flow simulation tools. The capabilities and limitations of a sequence of turbulence flow models, from the relatively simple k-£ model to direct numerical simulation and large eddy turbulence flow models, were considered for a range of petrochemical process equipment. Flow stability aspects and the potential of cellular automata for the simulation of industrial flows also received attention. The papers published in this special issue of Applied Scientific Research provide a fair representation of the Computational Fluid Dynamics topics discussed in the context of their application to petrochemical process equipment.

Download or read book Particles in Flows written by Tomáš Bodnár and published by Birkhäuser. This book was released on 2017-09-30 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to face particles in flows from many different, but essentially interconnected sides and points of view. Thus the selection of authors and topics represented in the chapters, ranges from deep mathematical analysis of the associated models, through the techniques of their numerical solution, towards real applications and physical implications. The scope and structure of the book as well as the selection of authors was motivated by the very successful summer course and workshop "Particles in Flows'' that was held in Prague in the August of 2014. This meeting revealed the need for a book dealing with this specific and challenging multidisciplinary subject, i.e. particles in industrial, environmental and biomedical flows and the combination of fluid mechanics, solid body mechanics with various aspects of specific applications.

Download or read book Stereoscopic Measurements of Particle Dispersion in Microgravity Turbulent Flow written by Daniel Eduardo Groszmann and published by . This book was released on 2001 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal was to compare the dispersion of different Stokes number particles in zero gravity and decouple the effects of inertia and gravity on the dispersion. Results show that higher inertia particles disperse less in zero gravity, in agreement with current models. Particles with St & ap; 200--300 dispersed about 110 of the dispersion measured in St & ap; 1 particles. Similarly, fluid points were shown to disperse 25 times as much as St & ap; 1 particles. Particles with more inertia also have particle velocity autocorrelations that decay more slowly. Comparisons are made with previous experimental work and indicate 40% less dispersion with gravity for St & ap; 1 particles and a slower decorrelation rate.

Download or read book Multiphase Flow Handbook Second Edition written by Efstathios Michaelides and published by CRC Press. This book was released on 2016-10-26 with total page 1559 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multiphase Flow Handbook, Second Edition is a thoroughly updated and reorganized revision of the late Clayton Crowe’s work, and provides a detailed look at the basic concepts and the wide range of applications in this important area of thermal/fluids engineering. Revised by the new editors, Efstathios E. (Stathis) Michaelides and John D. Schwarzkopf, the new Second Edition begins with two chapters covering fundamental concepts and methods that pertain to all the types and applications of multiphase flow. The remaining chapters cover the applications and engineering systems that are relevant to all the types of multiphase flow and heat transfer. The twenty-one chapters and several sections of the book include the basic science as well as the contemporary engineering and technological applications of multiphase flow in a comprehensive way that is easy to follow and be understood. The editors created a common set of nomenclature that is used throughout the book, allowing readers to easily compare fundamental theory with currently developing concepts and applications. With contributed chapters from sixty-two leading experts around the world, the Multiphase Flow Handbook, Second Edition is an essential reference for all researchers, academics and engineers working with complex thermal and fluid systems.

Download or read book Direct and Large Eddy Simulation I written by Peter R. Voke and published by Springer Science & Business Media. This book was released on 1994-10-31 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is a truism that turbulence is an unsolved problem, whether in scientific, engin eering or geophysical terms. It is strange that this remains largely the case even though we now know how to solve directly, with the help of sufficiently large and powerful computers, accurate approximations to the equations that govern tur bulent flows. The problem lies not with our numerical approximations but with the size of the computational task and the complexity of the solutions we gen erate, which match the complexity of real turbulence precisely in so far as the computations mimic the real flows. The fact that we can now solve some turbu lence in this limited sense is nevertheless an enormous step towards the goal of full understanding. Direct and large-eddy simulations are these numerical solutions of turbulence. They reproduce with remarkable fidelity the statistical, structural and dynamical properties of physical turbulent and transitional flows, though since the simula tions are necessarily time-dependent and three-dimensional they demand the most advanced computer resources at our disposal. The numerical techniques vary from accurate spectral methods and high-order finite differences to simple finite-volume algorithms derived on the principle of embedding fundamental conservation prop erties in the numerical operations. Genuine direct simulations resolve all the fluid motions fully, and require the highest practical accuracy in their numerical and temporal discretisation. Such simulations have the virtue of great fidelity when carried out carefully, and repre sent a most powerful tool for investigating the processes of transition to turbulence.

Download or read book Direct Numerical Simulations of Gas Liquid Multiphase Flows written by Grétar Tryggvason and published by Cambridge University Press. This book was released on 2011-03-10 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately predicting the behaviour of multiphase flows is a problem of immense industrial and scientific interest. Modern computers can now study the dynamics in great detail and these simulations yield unprecedented insight. This book provides a comprehensive introduction to direct numerical simulations of multiphase flows for researchers and graduate students. After a brief overview of the context and history the authors review the governing equations. A particular emphasis is placed on the 'one-fluid' formulation where a single set of equations is used to describe the entire flow field and interface terms are included as singularity distributions. Several applications are discussed, showing how direct numerical simulations have helped researchers advance both our understanding and our ability to make predictions. The final chapter gives an overview of recent studies of flows with relatively complex physics, such as mass transfer and chemical reactions, solidification and boiling, and includes extensive references to current work.

Download or read book Particle Dynamics in Turbulence written by Peter Dearborn Huck and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence is well known for its ability to efficiently disperse matter, whether it be atmospheric pollutants or gasoline in combustion motors. Two considerations are fundamental when considering such situations. First, the underlying flow may have a strong influence of the behavior of the dispersed particles. Second, the local concentration of particles may enhance or impede the transport properties of turbulence. This dissertation addresses these points separately through the experimental study of two different turbulent flows. The first experimental device used is the so-called von K\'arm\'an flow which consists of an enclosed vessel filled with water that is forced by two counter rotating disks creating a strongly inhomogeneous and anisotropic turbulence. Two high-speed cameras permitted the creation a trajectory data base particles that were both isodense and heavier than water but were smaller than the smallest turbulent scales. The trajectories of this data base permitted a study of the turbulent kinetic energy budget which was shown to directly related to the transport properties of the turbulent flow. The heavy particles illustrate the role of flow anisotropy in the dispersive dynamics of particles dominated by effects related to their inertia. The second flow studied was a wind tunnel seeded with micrometer sized water droplets which was used to study the effects of local concentration of the settling velocities of these particles. A model based on theoretical multi-phase methods was developed in order to take into account the role of collective effects on sedimentation in a turbulent flow. The theoretical results emphasize the role of coupling between the underlying flow and the dispersed phase.

Download or read book Flowing Matter written by Federico Toschi and published by Springer Nature. This book was released on 2019-09-25 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book, published in the Soft and Biological Matter series, presents an introduction to selected research topics in the broad field of flowing matter, including the dynamics of fluids with a complex internal structure -from nematic fluids to soft glasses- as well as active matter and turbulent phenomena. Flowing matter is a subject at the crossroads between physics, mathematics, chemistry, engineering, biology and earth sciences, and relies on a multidisciplinary approach to describe the emergence of the macroscopic behaviours in a system from the coordinated dynamics of its microscopic constituents. Depending on the microscopic interactions, an assembly of molecules or of mesoscopic particles can flow like a simple Newtonian fluid, deform elastically like a solid or behave in a complex manner. When the internal constituents are active, as for biological entities, one generally observes complex large-scale collective motions. Phenomenology is further complicated by the invariable tendency of fluids to display chaos at the large scales or when stirred strongly enough. This volume presents several research topics that address these phenomena encompassing the traditional micro-, meso-, and macro-scales descriptions, and contributes to our understanding of the fundamentals of flowing matter. This book is the legacy of the COST Action MP1305 “Flowing Matter”.

Download or read book Fundamentals of Dispersed Multiphase Flows written by S. Balachandar and published by Cambridge University Press. This book was released on 2024-03-28 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dispersed multiphase flows are frequently found in nature and have diverse geophysical, environmental, industrial, and energy applications. This book targets a beginning graduate student looking to learn about the physical processes that govern these flows, going from the fundamentals to the state of the art, with many exercises included.