Download or read book Numerical Study of Particle Interaction at Moderate Reynolds Numbers written by Asim Jadoon and published by . This book was released on 2008 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical simulations of hydrodynamic particle interactions at low particle reynolds number written by Salvador Vargas-Díaz and published by . This book was released on 2008 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particle Hydrodynamic Interactions in Intermediate Reynolds Number Flows written by Açmae El Yacoubi and published by . This book was released on 2013 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collective behavior and self-organization are ubiquitous mechanisms in nature. From animate creatures, such as swarming insects, flocking birds and schooling fish, to inanimate natural processes such as sedimentation and cloud formation, these phenomena arouse the curiosity of physicists and engineers alike. Early studies using analytical models and experiments in the low Reynolds number helped shed the light on the intricacies of particle interactions, as in clouds or arrays of spheres. In the intermediate Reynolds number regime however, the unsteadiness introduced by the fluid inertia, coupled to the object dynamics, add to the complexity of the problem. Numerical methods become then the tool par excellence to solve for these dynamics. The goal of this thesis is to lay out the foundations for a better understanding of particle interactions in fluids. Namely, we investigate the two-dimensional dynamics of interacting particles in a viscous fluid, in the intermediate Reynolds number range. We develop a direct numerical scheme based on the Immersed Interface Method to simulate the coupling of the dynamics of freely moving objects with the surrounding fluid. The method is used to study the dynamics of arrays of cylinders settling under gravity, and how these dynamics depend on the number of particles and their initial separation. We then provide a simple force law model which accounts for the initial repulsive force experienced by any two adjacent cylinders, at close range. When the particle density is high, collisions are almost inevitable. To treat close range interactions and resolve the interstitial flow in the narrowing gap between particles or between a particle and a wall, we further extend the immersed interface method to take into account the lubrication effects. We solve Reynolds equations and use the analytical solution in the lubrication region. Doing so enables us to avoid ad hoc methods where an artificial repulsive force is added or two-dimensional collision equations are used with a modified coefficient of restitution.

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 Study of Particle Rotation Effect in Gas Solid Flows Using Direct Numerical Simulation with a Lattice Boltzmann Method written by and published by . This book was released on 2014 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. An over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.

Download or read book Numerical Investigation of Particle fluid Interaction System Based on Discrete Element Method written by Hao Zhang and published by . This book was released on 2015 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the numerical investigation of the particle-fluid systems based on the Discrete Element Method (DEM). The whole thesis consists of three parts, in each part we have coupled the DEM with different schemes/solvers on the fluid phase. In the first part, we have coupled DEM with Direct Numerical Simulation (DNS) to study the particle-laden turbulent flow. The effect of collisions on the particle behavior in fully developed turbulent flow in a straight square duct was numerically investigated. Three sizes of particles were considered with diameters equal to 50 μm, 100 μm and 500 μm. Firstly, the particle transportation by turbulent flow was studied in the absence of the gravitational effect. Then, the particle deposition was studied under the effect of the wall-normal gravity force in which the influence of collisions on the particle resuspension rate and the final stage of particle distribution on the duct floor were discussed, respectively. In the second part, we have coupled DEM with Lattice Boltzmann Method (LBM) to study the particle sedimentation in Newtonian laminar flow. A novel combined LBM-IBM-DEM scheme was presented with its application to model the sedimentation of two dimensional circular particles in incompressible Newtonian flows. Case studies of single sphere settling in a cavity, and two particles settling in a channel were carried out, the velocity characteristics of the particle during settling and near the bottom were examined. At last, a numerical example of sedimentation involving 504 particles was finally presented to demonstrate the capability of the combined scheme. Furthermore, a Particulate Immersed Boundary Method (PIBM) for simulating the fluid-particle multiphase flow was presented and assessed in both two and three-dimensional applications. Compared with the conventional IBM, dozens of times speedup in two-dimensional simulation and hundreds of times in three-dimensional simulation can be expected under the same particle and mesh number. Numerical simulations of particle sedimentation in the Newtonian flows were conducted based on a combined LBM - PIBM - DEM showing that the PIBM could capture the feature of the particulate flows in fluid and was indeed a promising scheme for the solution of the fluid-particle interaction problems. In the last part, we have coupled DEM with averaged Navier-Stokes equations (NS) to study the particle transportation and wear process on the pipe wall. A case of pneumatic conveying was utilized to demonstrate the capability of the coupling model. The concrete pumping process was then simulated, where the hydraulic pressure and velocity distribution of the fluid phase were obtained. The frequency of the particles impacting on the bended pipe was monitored, a new time average collision intensity model based on impact force was proposed to investigate the wear process of the elbow. The location of maximum erosive wear damage in elbow was predicted. Furthermore, the influences of slurry velocity, bend orientation and angle of elbow on the puncture point location were discussed.

Download or read book Numerical Study of Particle and Droplet Interactions written by Lisa Prahl and published by . This book was released on 2006 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Study of the Translation of a Small Particle Along the Axis of a Circular Cylinder at Low Reynolds Numbers written by Max W. Pepper and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct and Large Eddy Simulation VI written by E. Lamballais and published by Springer Science & Business Media. This book was released on 2006-10-19 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sixth ERCOFTAC Workshop on ‘Direct and Large-Eddy Simulation’ (DLES-6) was held at the University of Poitiers from September 12-14, 2005. Following the tradition of previous workshops in the DLES-series, this edition has reflected the state-of-the-art of numerical simulation of transitional and turbulent flows and provided an active forum for discussion of recent developments in simulation techniques and understanding of flow physics.

Download or read book Hydrodynamic Interactions Between Particles in Low Reynolds Number Flow A Modular Approach written by S. Kim and published by . This book was released on 1984 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modular method for calculating hydrodynamic interactions between particles in low-Reynolds-number flow has been constructed by using multipole expansion solutions for the reflection field. The approach is made possible by the use of Faxen laws in relating the multipole moment to the incident field. The method is illustrated and checked by recalculating known expressions for the resistance and mobility tensors for two spheres. The method can be readily generalized to handle three-particle (or n-particle) interactions as shown in a following paper. New forms of the Faxen laws for prolate spheroids are given and will form the basis for other papers on spheroid-spheroid and spheroid-wall hydrodynamic interactions. The important result is that first-reflection solutions can be readily calculated even in cases where the ambient velocity field is obtained by a numerical procedure. These results, as asymptotic (far-field) solutions, furnish a check for more robust codes. In addition, these are important on their own since these provide crucial information for te renormalization theory used in suspension rheology.

Download or read book Shock Wave Boundary Layer Interactions written by Holger Babinsky and published by Cambridge University Press. This book was released on 2011-09-12 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1969 with total page 1090 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Particle Wave Interaction on Boundary Layers written by and published by . This book was released on 1994 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research program involves a computational study of the effects of disturbances generated from a moving particle on boundary layer transition. The practical importance of this problem stems from the fact that as an underwater vehicle moves through a particulate environment, particles enter the boundary layer and produce local disturbances. These disturbances may act as a bypass mechanism to transition and turbulence by interacting with boundary layer instabilities. The objective of this research is to study the basic mechanisms of the particle interaction and its effect on transition in the boundary layer. For this purpose, a direct numerical simulation is undertaken and the spherical particle is represented by a forcing function in the Navier Stokes equations. Results reveal good agreement with experimental studies. The report is presented in two parts. The first part concerns a general overview of the work accomplished and the second part summarizes our recent efforts on the modeling of steady/unsteady flow over a cylinder.

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 Fluid Structure Interactions in Low Reynolds Number Flows written by Camille Duprat and published by Royal Society of Chemistry. This book was released on 2016 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approachable introduction to low Reynolds number flows and elasticity for those new to the area across engineering, physics, chemistry and biology.

Download or read book Multiphase Flow Handbook written by Clayton T. Crowe and published by CRC Press. This book was released on 2005-09-19 with total page 1146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of the importance of multiphase flows in a wide variety of industries, including power, petroleum, and numerous processing industries, an understanding of the behavior and underlying theoretical concepts of these systems is critical. Contributed by a team of prominent experts led by a specialist with more than thirty years of experience, the Multiphase Flow Handbook provides such an understanding, and much more. It covers all aspects of multiphase flows, from fundamentals to numerical methods and instrumentation. The book begins with an introduction to the fundamentals of particle/fluid/bubble interactions followed by gas/liquid flows and methods for calculating system parameters. It includes up-to-date information on practical industrial applications such as boiling and condensation, fluidized beds, aerosols, separation systems, pollution control, granular and porous media flow, pneumatic and slurry transport, and sprays. Coverage then turns to the most recent information on particle/droplet-fluid interactions, with a chapter devoted to microgravity and microscale flows and another on basic multiphase interactions. Rounding out the presentation, the authors discuss numerical methods, state-of-the art instrumentation, and advanced experimental techniques. Supplying up-to-date, authoritative information on all aspects of multiphase flows along with numerous problems and examples, the Multiphase Flow Handbook is the most complete reference available for understanding the flow of multiphase mixtures.

Download or read book Droplets and Sprays written by Saptarshi Basu and published by Springer. This book was released on 2017-12-11 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on droplets and sprays relevant to combustion and propulsion applications. The book includes fundamental studies on the heating, evaporation and combustion of individual droplets and basic mechanisms of spray formation. The contents also extend to the latest analytical, numerical and experimental techniques for investigating the behavior of sprays in devices like combustion engines and gas turbines. In addition, the book explores several emerging areas like interactions between sprays and flames and the dynamic characteristics of spray combustion systems on the fundamental side, as well as the development of novel fuel injectors for specific devices on the application side. Given its breadth of coverage, the book will benefit researchers and professionals alike.