Download or read book A Lagrangian Approach for the Prediction of Particle Dispersion in Turbulent Flows written by Philippe Desjonqueres and published by . This book was released on 1988 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stochastic Lagrangian Modeling for Large Eddy Simulation of Dispersed Turbulent Two Phase Flows written by Abdallah Sofiane Berrouk and published by Bentham Science Publishers. This book was released on 2011 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the dispersion and the deposition of inertial particles convected by turbulent flows is a domain of research of considerable industrial interest. Inertial particle transport and dispersion are encountered in a wide range of flow configurations, whether they are of industrial or environmental character. Conventional models for turbulent dispersed flows do not appear capable of meeting the growing needs of chemical, mechanical and petroleum industries in this regard and physical environment testing is prohibitive. Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) ha.
Download or read book Analysis of Stochastic Methods for Predicting Particle Dispersion in Turbulent Flows written by Kyle Paul Sala and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current research seeks to develop a computational model that accurately describes particle dispersion in turbulent flow. Current particle dispersion models do not accurately predict the small-scale clumping of particles in turbulent flow that occurs due to interaction with turbulent eddies. A new stochastic vortex structure (SVS) model was developed and compared with current stochastic Lagrangian models (SLM) for turbulent flows. To examine what characteristics of the fluid flow field that lead to dispersion of particles, a number of non trivial measures were used. A discrete-element model is used to transport particle locations for cases with and without adhesive forces. Direct numerical simulations (DNS) are used as a baseline for comparison between the two models. Initial results show that the SVS model matches the spatial structure of the flow field of DNS reasonably well, while the SLMs do not. Investigation of particle collision rate suggest that while SVS matches the large length scales of flow, it omits the smaller scales of the flow.
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 New Approaches in Modeling Multiphase Flows and Dispersion in Turbulence Fractal Methods and Synthetic Turbulence written by F.C.G.A. Nicolleau and published by Springer Science & Business Media. This book was released on 2011-10-29 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a collection of the main contributions from the first five workshops held by Ercoftac Special Interest Group on Synthetic Turbulence Models (SIG42. It is intended as an illustration of the sig’s activities and of the latest developments in the field. This volume investigates the use of Kinematic Simulation (KS) and other synthetic turbulence models for the particular application to environmental flows. This volume offers the best syntheses on the research status in KS, which is widely used in various domains, including Lagrangian aspects in turbulence mixing/stirring, particle dispersion/clustering, and last but not least, aeroacoustics. Flow realizations with complete spatial, and sometime spatio-temporal, dependency, are generated via superposition of random modes (mostly spatial, and sometime spatial and temporal, Fourier modes), with prescribed constraints such as: strict incompressibility (divergence-free velocity field at each point), high Reynolds energy spectrum. Recent improvements consisted in incorporating linear dynamics, for instance in rotating and/or stably-stratified flows, with possible easy generalization to MHD flows, and perhaps to plasmas. KS for channel flows have also been validated. However, the absence of "sweeping effects" in present conventional KS versions is identified as a major drawback in very different applications: inertial particle clustering as well as in aeroacoustics. Nevertheless, this issue was addressed in some reference papers, and merits to be revisited in the light of new studies in progress.
Download or read book Dispersion and Deposition of Heavy Particles in Turbulent Flows written by Chunyu Jin and published by . This book was released on 2012 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulations of Turbulent Dispersion Around Buildings Via a Lagrangian Stochastic Particle Model written by and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes a numerical modeling approach that can be used to provide estimates of air concentrations due to emissions at industrial sites or other sites where buildings may have an important impact on the dispersion patterns. The procedure consists of two sequential steps: (i) Prediction of mean flow and turbulence fields via a turbulent flow model; and, (ii) Employment of the calculated flow and Turbulence fields to drive a Lagrangian Stochastic Particle Model. Two flow scenarios in which the approaching mean wind is assumed to be at 90° and 30° to the building complex are used as input to the Lagrangian model. The first calculation is based on an earlier transport and diffusion simulation that employed an existing particle-in-cell flux-gradient dispersion model. The second simulation is used to demonstrate the strong spatial variations that the concentration field exhibit within the highly complex separation zones of building wakes. The relationship between concentration levels and toxic load are discussed for the case of a chemical spill.
Download or read book Turbulent Reactive Flows written by R. Borghi and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent reactive flows are of common occurrance in combustion engineering, chemical reactor technology and various types of engines producing power and thrust utilizing chemical and nuclear fuels. Pollutant formation and dispersion in the atmospheric environment and in rivers, lakes and ocean also involve interactions between turbulence, chemical reactivity and heat and mass transfer processes. Considerable advances have occurred over the past twenty years in the understanding, analysis, measurement, prediction and control of turbulent reactive flows. Two main contributors to such advances are improvements in instrumentation and spectacular growth in computation: hardware, sciences and skills and data processing software, each leading to developments in others. Turbulence presents several features that are situation-specific. Both for that reason and a number of others, it is yet difficult to visualize a so-called solution of the turbulence problem or even a generalized approach to the problem. It appears that recognition of patterns and structures in turbulent flow and their study based on considerations of stability, interactions, chaos and fractal character may be opening up an avenue of research that may be leading to a generalized approach to classification and analysis and, possibly, prediction of specific processes in the flowfield. Predictions for engineering use, on the other hand, can be foreseen for sometime to come to depend upon modeling of selected features of turbulence at various levels of sophistication dictated by perceived need and available capability.
Download or read book Building a Turbulent Jet written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanics of how particles diffuse, interact, eject, etc. within a fluid is applicable to numerous industrial and environmental applications. Unwanted products of combustion, dust contamination of solar panels, pathogen transport during a cough and ejections of particles during volcanic eruptions, are a few examples of flows in which increased knowledge of particle dynamics could result in substantial reduction of negative environmental and economic impacts. To better understand the tendencies of particles within shearing flows (such as jets), an extensive experimental campaign was conducted. Measurements of a turbulent round water jet were performed within an icosahedral tank. Particle tracking velocimetry was employed to create three-component, three-dimensional trajectories. Particles of varying size and weight were used to seed the flow in order to provide a range of inertial effects based on the particle interaction with the fluid. Numerous Eulerian and Lagrangian parameters were characterized and most notable, a trajectory stationarization technique was successfully implemented to address the inhomogeneity of the flow field. This approach could be extended to provide systematic methods to analyze complicated flow fields, enhancing knowledge of their dynamics. Alternatively, theoretical models of particle mechanics have been constructed, contributing to the baseline understanding of Lagrangian dynamics. Stochastic processes and phenomenological approaches are presented to accurately predict the low-order statistics of tracers, point particles which follow the motion of the fluid, for the idealized flow of homogeneous, isotropic and stationary turbulence (i.e. without the inclusions of external forces).
Download or read book On the Full Lagrangian Approach and Thermophoretic Deposition in Gas particle Flows written by David Patrick Healy and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical and experimental studies of particle deposition in turbulent pipe flow have been carried out for over forty years, but some of the most important transport mechanisms are still not well understood. The first part of this thesis is concerned with the calculation of particle density when using Lagrangian methods to predict inertial particle transport in two-dimensional laminar fluid flows. Traditionally, Lagrangian calculations involve integrating the particle equations of motion along particle pathlines, and the particle density is obtained by applying a statistical averaging procedure to those pathlines which intersect a particular computational grid cell. Unfortunately, extremely large numbers of particles are required to reduce the statistical errors to acceptable levels, and this makes the method computationally expensive. Recently, the Full Lagrangian approach has been developed, which allows the direct calculation of the particle density along particle pathlines. This method had previously been applied only to simple analytical flow fields. The application of the method to CFD generated fluid velocity fields was shown to be possible, and the results obtained using the Full Lagrangian approach were compared to those from a traditional Lagrangian approach. It was found that better quality solutions could be obtained with the use of far fewer particle pathlines. An analysis of the manner in which the Full Lagrangian approach deals with particles whose paths cross each other (and the resulting discontinuity in particle density) was also undertaken, and this illustrates the sophistication of the method. The second part of the thesis comprises an experimental and theoretical study of the deposition of small particles in turbulent flows by thermophoresis. Thermophoresis is the phenomenon whereby small particles suspended in a gas in which there exists a temperature gradient experience a force in the direction opposite from that of the temperature gradient. Previous researchers have attempted to impose a radial temperature difference in pipe flow experiments, but have not yet succeeded in attaining a constant thermophoretic force along the length of the pipe. This limits the accuracy and usefulness of the data for the validation of theoretical expressions for the thermophoretic fluxes. An experimental rig has been designed to achieve a constant thermophoretic force. This was done by using an annular geometry with a cold inner wall and hot outer wall. The particle size was varied and the deposition flux was measured for turbulent flow with three temperature differences. The deposition fluxes for small particles were found to be independent of dimensionless particle size, with each increase in temperature difference resulting in an increase in magnitude of the flux. Evidence of a thermophoresis-turbulence coupling was found for intermediate-sized particles, and large particles were not influenced by thermophoresis. A theory of particle deposition, developed for the case of turbulent pipe flow, was modified to study flow in a turbulent annulus, so that theoretical expressions for the thermophoretic fluxes could be included and compared with the experimental results. Agreement with experimental data was quite good, but some deficiencies in a widely used theoretical expression for the thermophoretic flux were exposed. An alternative expression was used, which gave much better agreement with the experimental data, and the mechanisms behind the thermophoresis-turbulence coupling were also investigated. The validation of this expression for the thermophoretic force will allow its inclusion in numerical studies of particle deposition in more complex geometries.
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 Chemical Reactivity in Liquids written by Michael Moreau and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding chemical reactivity has been the permanent concern of chemists from time immemorial. If we were able to understand it and express it quantitatively there would practically remain no unsolved mystery, and reactions would be fully predictable, with their products and rates and even side reactions. The beautiful developments of thermodynamics through the 19th century supplied us with the knowledge of the way a reactions progresses, and the statistical view initiated by Gibbs has progressively led to an unders tanding closer to the microscopic phenomena. But is was always evident to all that these advances still left our understanding of chemical reactivity far behind our empirical knowledge of the chemical reaction in its practically infinite variety. The advances of recent years in quantum chemistry and statistical mechanics, enhanced by the present availability of powerful and fast compu ters, are very fast changing this picture, and bringing us really close to a microscopic understanding of chemical equilibria, reaction rates, etc.... This is the reason why our Society encouraged a few years ago the initiative of Professor Savo Bratos who, with a group of French colleagues, prepared an impressive study on "Reactivite chimique en phase liquide", a prospective report which was jointly published by the Societe Fran
Download or read book 27th European Symposium on Computer Aided Process Engineering written by and published by Elsevier. This book was released on 2017-09-21 with total page 3064 pages. Available in PDF, EPUB and Kindle. Book excerpt: 27th European Symposium on Computer Aided Process Engineering, Volume 40 contains the papers presented at the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event held in Barcelona, October 1-5, 2017. It is a valuable resource for chemical engineers, chemical process engineers, researchers in industry and academia, students, and consultants for chemical industries. - Presents findings and discussions from the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event
Download or read book Proceedings of 16th Asian Congress of Fluid Mechanics written by L. Venkatakrishnan and published by Springer Nature. This book was released on 2021-02-03 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes select papers presented during the 16th Asian Congress of Fluid Mechanics, held in JNCASR, Bangalore, and presents the latest developments in computational, experimental and theoretical research as well as industrial and technological advances. This book is of interest to researchers working in the field of fluid mechanics.
Download or read book Mixing and Dispersion in Flows Dominated by Rotation and Buoyancy written by Herman J.H. Clercx and published by Springer. This book was released on 2017-10-24 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a state-of-the-art overview of current developments in the field in a way accessible to attendees coming from a variety of fields. Relevant examples are turbulence research, (environmental) fluid mechanics, lake hydrodynamics and atmospheric physics. Topics discussed range from the fundamentals of rotating and stratified flows, mixing and transport in stratified or rotating turbulence, transport in the atmospheric boundary layer, the dynamics of gravity and turbidity currents eventually with effects of background rotation or stratification, mixing in (stratified) lakes, and the Lagrangian approach in the analysis of transport processes in geophysical and environmental flows. The topics are discussed from fundamental, experimental and numerical points of view. Some contributions cover fundamental aspects including a number of the basic dynamical properties of rotating and or stratified (turbulent) flows, the mathematical description of these flows, some applications in the natural environment, and the Lagrangian statistical analysis of turbulent transport processes and turbulent transport of material particles (including, for example, inertial and finite-size effects). Four papers are dedicated to specific topics such as transport in (stratified) lakes, transport and mixing in the atmospheric boundary layer, mixing in stratified fluids and dynamics of turbidity currents. The book is addressed to doctoral students and postdoctoral researchers, but also to academic and industrial researchers and practicing engineers, with a background in mechanical engineering, applied physics, civil engineering, applied mathematics, meteorology, physical oceanography or physical limnology.
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 Statistical Treatment of Turbulent Polydisperse Particle Systems written by J.S. Shrimpton and published by Springer. This book was released on 2014-06-20 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book we will introduce the modeling process of turbulent particulate flows which are encountered in many engineering and environmental applications. These types of flows usually also involve heat and mass transfer and turbulence adds another dimension to the complexity of the problem and hence a rigorous mathematical treatment is usually required. This required mathematical background makes the learning curve for new research students and practicing engineers extremely steep. Therefore modeling process for new or existing problems is extremely slow and is usually restricted to minor improvements to the to the available models. In this book we try to gather the required mathematical knowledge and introduce them more intuitively. Many numerical simulations of basic processes and equation will be given to provide the reader with a physical understanding of the different terms in the underlying equations. We will start the modeling process from a mesoscopic level which deals with the system of an intermediate length scale between the size of the atoms or molecules and the bulk of the material. This provides a unique opportunity for the reader to intuitively add different phenomena to their models and equipped with the necessary mathematical tools derive the final models for their problems.
