Download or read book Turbulence Modulation by Non spherical Particles written by Matthias Mandø and published by . This book was released on 2009 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics of Non spherical Particles in Turbulence written by Luis Blay Esteban and published by . This book was released on 2020 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies the dynamics of 2D objects moving through turbulent fluids. It examines the decay of turbulence over extended time scales, and compares the dynamics of non-spherical particles moving through still and turbulent fluids. The book begins with an introduction to the project, its aims, and its relevance for industrial applications. It then discusses the movement of planar particles in quiescent fluid, and presents the numerous methodologies used to measure it. The book also presents a detailed analysis of the falling style of irregular particles, which makes it possible to estimate particle trajectory and wake morphology based on frontal geometry. In turn, the book provides the results of an analysis of physically constrained decaying turbulence in a laboratory setting. These results suggest that large-scale cut-off in numerical simulations can result in severe bias in the computed turbulent kinetic energy for long waiting times. Combining the main text with a wealth of figures and sketches throughout, the book offers an accessible guide for all engineering students with a basic grasp of fluid mechanics, while the key findings will also be of interest to senior researchers.

Download or read book Dynamics of Non Spherical Particles in Turbulence written by Luis Blay Esteban and published by Springer. This book was released on 2019-08-13 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies the dynamics of 2D objects moving through turbulent fluids. It examines the decay of turbulence over extended time scales, and compares the dynamics of non-spherical particles moving through still and turbulent fluids. The book begins with an introduction to the project, its aims, and its relevance for industrial applications. It then discusses the movement of planar particles in quiescent fluid, and presents the numerous methodologies used to measure it. The book also presents a detailed analysis of the falling style of irregular particles, which makes it possible to estimate particle trajectory and wake morphology based on frontal geometry. In turn, the book provides the results of an analysis of physically constrained decaying turbulence in a laboratory setting. These results suggest that large-scale cut-off in numerical simulations can result in severe bias in the computed turbulent kinetic energy for long waiting times. Combining the main text with a wealth of figures and sketches throughout, the book offers an accessible guide for all engineering students with a basic grasp of fluid mechanics, while the key findings will also be of interest to senior researchers.

Download or read book TURBULENCE MODULATION UNDER LARGE PARTICLE LOADING written by Aidan Stephen Cronin and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle-laden turbulence is important to a diverse range of topics: from aerosol transport in the atmosphere to flocculation techniques treating our drinking water. Often the particles in flows of interest are large and non-spherical, making them difficult to study, and so simplified cases are considered to quantify turbulent behaviors. Experimental laboratory research has provided insight into the quantifiable behavior of these simplified particle-laden flows, notably in cases of homogeneous and isotropic (H.I) turbulence. For this research, we designed and constructed a novel laboratory turbulence tank for the study of particle-laden flows that could create a region of H.I turbulence at its center. To do so, we incorporated random, symmetric forcing on a completely new geometry (a modified icosahedron) intending to maintain the properties of H.I. turbulence while increasing the size of the region of the tank in which it is contained. This facility will provide a unique testbed for studies of particle-laden turbulence.

Download or read book Study of Turbulence Modulation by Finite size Solid Particles with the Lattice Boltzmann Method written by Cheng Peng and published by . This book was released on 2018 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent flows laden with finite-size solid particles are found in a variety of natural and engineering processes. However, the overall understanding of how the flow properties, such as turbulent intensity and flow drag, are modified by the addition of the particles is still limited. So far, the only rigorous approach to investigate the modulation mechanisms at the particle scale is to numerically solve the disturbance flow around each particle, known as the interface-resolved simulations (IRS). However, the application of IRS in the turbulent particle-laden flow is particularly challenging due to the requirements of resolving all the length and time scales in the turbulent flow, as well as the need to realize the no-slip boundary condition on the moving particle surfaces. ☐ In recent years, the lattice Boltzmann method (LBM) has emerged as an efficient and accurate numerical approach for computational fluid dynamics. Compared to the conventional approaches of directly solving the Navier-Stokes equations, LBM is simple to code, easy to parallelize, and flexible in treating boundary conditions. In particular, the no-slip boundary treatment based on bounce-back scheme and mesoscopic momentum exchange in LBM take full advantage of the gas kinetic description. However, the realization of these treatments in particle-laden turbulent flow simulations is still rare. So far, the majority of the particle-laden turbulent flow simulations relies on the smoothed-boundary treatments, such as the immersed boundary methods, which tends to induce artificial dissipation. In this dissertation, LBM with a sharp-interface treatment is developed to investigate turbulence modulation by finite-size solid particles. ☐ After a thorough validation, the method is applied to the simulations of a turbulent channel flow laden with both fixed and moving particles. The interactions between the dispersed particles and carrier turbulent flows, especially the modulation induced by the particles on the turbulence intensity and its parameter dependence are examined. The addition of particles is found to result in a more homogeneous distribution of turbulent kinetic energy (TKE) in the wall normal direction and a more isotropic TKE distribution among different spatial directions, comparing to the single-phase turbulent channel flow. To gain further insight, the budget equations of both the total TKE and component-wise TKE in the particle-laden turbulent flows are derived and analyzed using the simulation data. The budget analysis of the total TKE shows that the production rate of TKE from the mean flow is modified to become more uniform in the wall-normal direction by the presence of particles, which is responsible for the more homogeneous distribution of TKE. Specifically, in the buffer region where the TKE source is maximized in the single-phase flow, the TKE source due to the mean shear is reduced since both the mean flow velocity gradient and the Reynolds stress are reduced by the presence of particles. This reduction is found to be related to the particle inertia, where particles with larger inertia result in greater reduction of the TKE source. On the other hand, particles pump energy to turbulent fluctuations by doing work directly (moving particles) or inducing disturbances to the mean flow (fixed particles), converting more mechanical energy from the mean flow to the turbulent motion. The strength of this extra TKE source is related to the dynamics of the wake developed behind particles and therefore is particle-Reynolds-number dependent. The relative strength of the above two mechanisms determines whether the turbulence intensity of a turbulent channel flow is augmented or attenuated by the presence of particles. The budget analysis of component-wise TKE reveals that the more isotropic distribution of TKE among different spatial directions results from the enhanced inter-components transfer of TKE. This enhancement is found to originate from the spherical shape of the particles and particle rotation. ☐ In summary, the improved LBM simulation method based on the sharp-interface treatment provides a better alternative for particle-laden turbulent flow simulations than the commonly used smoothed-interface treatments. The physical results from this dissertation research advance our understanding of flow modulation induced by finite-size solid particles in turbulent flows, particularly in wall-bounded turbulent flows.

Download or read book Turbulence Modulation in Particle laden Flows written by John D. Schwarzkopf and published by . This book was released on 2008 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluid Dynamics of Particles Drops and Bubbles written by and published by Cambridge University Press. This book was released on with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulence Modulation in Gas particle Flows a Comparison of Selected Models written by Sarah M. Hodgson and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of turbulence modulation, the process whereby the gas-phase turbulence is modified by the presence of particles, is investigated. Experimental trends are examined and parameters affecting turbulence modulation and the mechanisms by which turbulence modulation occurs are identified. A new model that accounts for the crossing trajectory effect is presented. This model and the turbulence modulation models of Chen and Wood [4], Tu and Fletcher [45], and Mostafa and Mongia [30] are investigated using the TASCflow CFD code. The models are compared with the experimental results of Tsuji et al [44]. The model of Tu and Fletcher is not able to reproduce either general experimental trends or the experimental results, while the other three models can predict the general experimental trends but cannot reproduce the experimental results. Analysis shows that the turbulent viscosity, [mu]'t', plays an important role in modifying the turbulence intensity profiles. The new model was not able to capture the crossing trajectory effect for the flow considered.

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 Proceedings of the IUTAM Symposium on Turbulent Structure and Particles Turbulence Interaction written by Xiaojing Zheng and published by Springer Nature. This book was released on 2024-01-02 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the proceedings of the 'IUTAM Symposium on Turbulent Structure and Particles' held in 2023. It provides a comprehensive overview of the latest research and developments in the field of turbulent dispersed multiphase flows. The book features contributions from experts in academia and industry, covering a range of topics including droplet and pollutant dispersion, sand/dust storms, sediment transport in water or air flows, fluidized beds, bubbly flows and more. The content is a valuable reference for researchers, engineers, and students who are interested in understanding the complex behavior of multiphase flows in different natural and industrial environments.

Download or read book Visualization of Turbulence Modulation with Large Particles written by Franz Demetrius Davis and published by . This book was released on 1993 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulence Modulation and Dense Spray Structure written by R. N. Parthasarathy and published by . This book was released on 1988 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical and experimental study of phenomena related to dense sprays is described. Two aspects of dense sprays are being considered: effects of turbulence modulation, which is the direct effect of particle (drop) motion on the turbulence properties of multiphase flows; and the structure and mixing properties of the dense-spray region of pressure atomized sprays. Turbulence modulation is being studied by considering spherical monodisperse glass particles falling in a stagnant water bath, where effects of turbulence modulation are responsible for the entire turbulence field. Measurements involve phase velocities and temporal and spatial correlations and spectra of the continuous phase velocities using a two-point phase-discriminating laser Doppler anemometer. Flow properties are being analyzed using stochastic methods: assuming linear superposition of randomly arriving particle wakes (Poisson statistics) for liquid phase properties; and random-walk calculations based on statistical time-series methods for particle properties. Multiphase flow, Sprays, Particle-laden flow. (jes).

Download or read book Sustained Simulation Performance 2017 written by Michael M. Resch and published by Springer. This book was released on 2017-10-24 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state of the art in High Performance Computing on modern supercomputer architectures. It addresses trends in hardware and software development in general, as well as the future of High Performance Computing systems and heterogeneous architectures. The contributions cover a broad range of topics, from improved system management to Computational Fluid Dynamics, High Performance Data Analytics, and novel mathematical approaches for large-scale systems. In addition, they explore innovative fields like coupled multi-physics and multi-scale simulations. All contributions are based on selected papers presented at the 24th Workshop on Sustained Simulation Performance, held at the University of Stuttgart’s High Performance Computing Center in Stuttgart, Germany in December 2016 and the subsequent Workshop on Sustained Simulation Performance, held at the Cyberscience Center, Tohoku University, Japan in March 2017.

Download or read book Turbulence Modulation in Particle Laden Flow with Mono Dispersed Droplets written by 呂偉福 and published by . This book was released on 2010 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct and Large Eddy Simulation XII written by Manuel García-Villalba and published by Springer Nature. This book was released on 2020-05-09 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 12th instalment in the bi-annual Workshop series on Direct and Large Eddy Simulation (DLES), which began in 1994 and focuses on modern techniques used to simulate turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structure. With the rapidly expanding capacities of modern computers, this approach has attracted more and more interest over the years and will undoubtedly be further enhanced and applied in the future. Hybrid modelling techniques based on a combination of LES and RANS approaches also fall into this category and are covered as well. The goal of the Workshop was to share the state of the art in DNS, LES and related techniques for the computation and modelling of turbulent and transitional flows. The respective papers highlight the latest advances in the prediction, understanding and control of turbulent flows in academic and industrial applications.

Download or read book Micropolar Fluids written by Grzegorz Lukaszewicz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micropolar fluids are fluids with microstructure. They belong to a class of fluids with nonsymmetric stress tensor that we shall call polar fluids, and include, as a special case, the well-established Navier-Stokes model of classical fluids that we shall call ordinary fluids. Physically, micropolar fluids may represent fluids consisting of rigid, randomly oriented (or spherical) particles suspended in a viscous medium, where the deformation of fluid particles is ignored. The model of micropolar fluids introduced in [65] by C. A. Eringen is worth studying as a very well balanced one. First, it is a well-founded and significant generalization of the classical Navier-Stokes model, covering, both in theory and applications, many more phenomena than the classical one. Moreover, it is elegant and not too complicated, in other words, man ageable to both mathematicians who study its theory and physicists and engineers who apply it. The main aim of this book is to present the theory of micropolar fluids, in particular its mathematical theory, to a wide range of readers. The book also presents two applications of micropolar fluids, one in the theory of lubrication and the other in the theory of porous media, as well as several exact solutions of particular problems and a numerical method. We took pains to make the presentation both clear and uniform.

Download or read book Direct and Large Eddy Simulation X written by Dimokratis G.E. Grigoriadis and published by Springer. This book was released on 2017-10-06 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses nearly all aspects of the state of the art in LES & DNS of turbulent flows, ranging from flows in biological systems and the environment to external aerodynamics, domestic and centralized energy production, combustion, propulsion as well as applications of industrial interest. Following the advances in increased computational power and efficiency, several contributions are devoted to LES & DNS of challenging applications, mainly in the area of turbomachinery, including flame modeling, combustion processes and aeroacoustics. The book includes work presented at the tenth Workshop on 'Direct and Large-Eddy Simulation' (DLES-10), which was hosted in Cyprus by the University of Cyprus, from May 27 to 29, 2015. The goal of the workshop was to establish a state of the art in DNS, LES and related techniques for the computation and modeling of turbulent and transitional flows. The book is of interest to scientists and engineers, both in the early stages of their career and at a more senior level.