Particle Dispersion and Inter-phase Kinetic Energy Transfer in a Turbulent, Two-phase Shear Layer


Book Description

The transport of heavy, polydispersed particles and the inter-phase transfer of kinetic energy is measured experimentally in a turbulent shear layer. Specifically, fundamental/subharmonic forcing and conditional-averaging techniques were used to study the particle/turbulence interaction with the large-scale, spanwise, coherent vortices, starting from their initial roll-up through the first pairing event. It is shown that the pairing event plays a homogenizing role on the particulate field, but the amount of homogenization is strongly dependent upon the particle's viscous relaxation time, the eddy turnover time, as well as the time the particles are allowed to interact with each scale prior to a pairing event. Thus, even though the smaller size particles become well-mixed across the structure, the larger sizes are still dispersed in an inhomogeneous fashion. The dispersed/carrier phase coupling was examined through the measurement of conditionally-averaged kinetic energy transfer (which results from the work done to accelerate or decelerate the dispersed phase), as well as the conditionally-averaged particle dissipation (energy dissipated by shear deformation in the carrier phase due to the relative slip between the particles and the carrier fluid).










Modeling Approaches and Computational Methods for Particle-laden Turbulent Flows


Book Description

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







Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes


Book Description

Challenging problems involvrllg jet and plume phenomena are common to many areas of fundamental and applied scientific research, and an understanding of plume and jet behaviour is essential in many geophysical and industrial contexts. For example, in the field of meteorology, where pollutant dispersal takes place by means of atmospheric jets and plumes formed either naturally under conditions of convectively-driven flow in the atmospheric boundary layer, or anthropogenically by the release of pollutants from tall chimneys. In other fields of geophysics, buoyant plumes and jets are known to play important roles in oceanic mixing processes, both at the relatively large scale (as in deep water formation by convective sinking) and at the relatively small scale (as with plume formation beneath ice leads, for example). In the industrial context, the performances of many engineering systems are determined primarily by the behaviour of buoyant plumes and jets. For example, (i) in sea outfalls, where either sewage or thermal effluents are discharged into marine and/or freshwater environments, (ii) in solar ponds, where buoyant jets are released under density interfaces, (iii) in buildings, where thermally-generated plumes affect the air quality and ventilation properties of architectural environments, (iv) in rotating machinery where fluid jet~ are used for cooling purposes, and (v) in long road and rail tunnels, where safety and ventilation prcedures rely upon an understanding of the behaviour of buoyant jets. In many other engineering and oceanographic contexts, the properties of jets and plumes are of great importance.







Droplets and Sprays


Book Description

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.