Download or read book Experimental Study of Particle induced Turbulence Modification in the Presence of a Rough Wall written by Godwin Fabiola Kwaku Tay and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 An Experimental Study of Particle wall Collision Relating to Flow of Solid Particles in a Fluid written by Michael Herbert McLaughlin and published by . This book was released on 1968 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of Turbulence Production Near a Smooth Wall in a Turbulent Boundary Layer with Zero Pressure gradient written by Heung-tae Kim and published by . This book was released on 1968 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of the turbulent boundary layer on a smooth wall with zero pressure gradient has been studied experimentally. Emphasis has been given to the production of turbulence in the inner layers. Intensive studies of a few.

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 Nuclear Science Abstracts written by and published by . This book was released on 1975-08 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of Turbulence Production Mechanisms in Boundary Layer Flows written by R. E. Falco and published by . This book was released on 1982 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The major goal of this research has been to identify the mechanisms responsible for turbulence production near smooth walls. Although many dynaical features of the turbulence production process have been previously identified, and many models proposed to explain how these features came to be, the reasons for their existence, and for their evolution into turbulent eruptions are stil not satisfactorily understood. The coherence associated with the production of turbulence near a wall is greater than anticipated before this investigation began. It is clear that many aspects of the physics can be modelled by the vortex ring/wall interaction, however, it appears that somewhat less stringent conditions can also initiate new production. Furthermore, the same physics appears to govern production for Reynolds numbers up to the onset of the law of the wake (which signals the onset of high Reynolds number asymptotic behavior). However, further investigation is required to determine which details of the interactions are necessary and which are sufficient, before attempts at logically modifying the production rate can be made.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modification of Particle Laden Near wall Turbulence in a Vertical Channel Bounded by Rough Walls written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 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 Turbulence Modification in Dispersed Multiphase Flows written by Efstathios Michaelides and published by . This book was released on 1989 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Instabilities in Multiphase Flows written by A. Berlemont and published by . This book was released on 2014-01-15 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulence in Open Channel Flows written by Hiroji Nakagawa and published by Routledge. This book was released on 2017-10-02 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of open channel turbulence, focusing especially on certain features stemming from the presence of the free surface and the bed of a river. Part one presents the statistical theory of turbulence; Part two addresses the coherent structures in open-channel flows and boundary layers.

Download or read book Fundamentals of Multiphase Flow written by Christopher E. Brennen and published by Cambridge University Press. This book was released on 2005-04-18 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publisher Description

Download or read book Basics of Engineering Turbulence written by David Ting and published by Academic Press. This book was released on 2016-02-23 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Basics of Engineering Turbulence introduces flow turbulence to engineers and engineering students who have a fluid dynamics background, but do not have advanced knowledge on the subject. It covers the basic characteristics of flow turbulence in terms of its many scales. The author uses a pedagogical approach to help readers better understand the fundamentals of turbulence scales, especially how they are derived through the order of magnitude analysis. This book is intended for those who have an interest in flowing fluids. It provides some background, though of limited scope, on everyday flow turbulence, especially in engineering applications. The book begins with the ‘basics’ of turbulence which is necessary for any reader being introduced to the subject, followed by several examples of turbulence in engineering applications. This overall approach gives readers all they need to grasp both the fundamentals of turbulence and its applications in practical instances. Focuses on the basics of turbulence for applications in engineering and industrial settings Provides an understanding of concepts that are often challenging, such as energy distribution among the turbulent structures, the effective diffusivity, and the theory behind turbulence scales Offers a user-friendly approach with clear-and-concise explanations and illustrations, as well as end-of-chapter problems

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: