May 6, 2021

Download Ebook Free Direct Numerical Simulation And Multiscale Modelling

Direct Numerical Simulation and Multiscale Modelling

Direct Numerical Simulation and Multiscale Modelling
Author : Kai Luo
Publisher : Academic Press
Release Date : 2021-04
Category :
Total pages :129
GET BOOK

Direct Numerical Simulation and Multiscale Modelling provides a unified description of DNS, LES and RANS in the context of broader modelling and simulation practice. The relevance of these techniques to flow, turbulence, combustion and multiphysics is explained to help readers apply them to a wide range of research topics. Introductory sections help readers get up to speed with the theories of turbulence, combustion, and multiphysics, along with the basics of simulation and modelling. This is followed by thorough treatments of the numerical methods, boundary conditions, and specific modelling approaches for different purposes. Applications in fields including aerospace, biomedical, and chemical engineering are investigated where appropriate. This is the ideal guide for readers interested in direct numerical simulation, or modelling/simulation of turbulence more generally, who need an overview of the methods available and advice on how to select and implement the correct one.

Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage

Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage
Author : Alejandro A. Franco,Marie Liesse Doublet,Wolfgang G. Bessler
Publisher : Springer
Release Date : 2015-11-12
Category : Technology & Engineering
Total pages :249
GET BOOK

The aim of this book is to review innovative physical multiscale modeling methods which numerically simulate the structure and properties of electrochemical devices for energy storage and conversion. Written by world-class experts in the field, it revisits concepts, methodologies and approaches connecting ab initio with micro-, meso- and macro-scale modeling of components and cells. It also discusses the major scientific challenges of this field, such as that of lithium-ion batteries. This book demonstrates how fuel cells and batteries can be brought together to take advantage of well-established multi-scale physical modeling methodologies to advance research in this area. This book also highlights promising capabilities of such approaches for inexpensive virtual experimentation. In recent years, electrochemical systems such as polymer electrolyte membrane fuel cells, solid oxide fuel cells, water electrolyzers, lithium-ion batteries and supercapacitors have attracted much attention due to their potential for clean energy conversion and as storage devices. This has resulted in tremendous technological progress, such as the development of new electrolytes and new engineering designs of electrode structures. However, these technologies do not yet possess all the necessary characteristics, especially in terms of cost and durability, to compete within the most attractive markets. Physical multiscale modeling approaches bridge the gap between materials’ atomistic and structural properties and the macroscopic behavior of a device. They play a crucial role in optimizing the materials and operation in real-life conditions, thereby enabling enhanced cell performance and durability at a reduced cost. This book provides a valuable resource for researchers, engineers and students interested in physical modelling, numerical simulation, electrochemistry and theoretical chemistry.

Multiscale Direct Numerical Modeling of Pore-scale and Darcy-scale Multiphase Flow in Porous Media

Multiscale Direct Numerical Modeling of Pore-scale and Darcy-scale Multiphase Flow in Porous Media
Author : Soheil Esmaeilzadeh
Publisher : Unknown
Release Date : 2021
Category :
Total pages :129
GET BOOK

Improving our understanding about the evolution of multiphase flow in porous media is crucial for many applications such as extraction of hydrocarbons and geothermal energy from subsurface reservoirs, ground-water remediation, CO2 capture and storage, and transport of contaminants in aquifers and soil. Although such applications have implications at very large length scales, e.g., in the orders of kilometers, they strongly depend on the complex physics and dynamics that mainly occur at the pore-scale. Studying multiphase flow at the pore-scale using direct numerical modeling requires developing accurate numerical frameworks that not only honor conservation laws of mass, momentum, and energy, but also can precisely represent and track fluid-fluid interfaces in space and time in the presence of complex embedded solid geometries. In this dissertation, we consider incompressible and immiscible two-phase flows under isothermal conditions and in electrokinetic equilibrium. We solve for the conservation of mass and momentum, and using an immersed boundary approach account for the presence of embedded solid boundaries. We use a two-phase flow modeling approach based on the level-set method to capture the interfacial dynamics of the flow. Using our numerical framework, we first validate recent experimental works on phase separation in the form of pinch-off at the pore-scale, then we extend such experimental observations to a wide range of wettability conditions. For the phase separation in the form of pinch-off, we provide a quantitative study of the emerging length and time scales and their dependence on the wettability conditions, capillary effects, and viscous forces. Afterward, we present a subgrid thin-film model in order to resolve the interfacial dynamics of thin-films on curved solid surfaces in porous media. We couple a Navier-Stokes solver with a topology-preserving level-set method and a sub-grid thin-film model in order to simulate immiscible two-phase pore-scale flows in the presence of thin-films on curved solid surfaces. We validate our proposed subgrid thin-film model for the cases of static and dynamic fluid-fluid interfaces in capillary tubes (both drainage and imbibition) in the presence of curved solid surfaces. We compare the thin-film profile obtained by the subgrid thin-film model versus the profile numerically resolved by refined computational grid cells spanning the subgrid resolution of the thin-film and achieve a great agreement. Subsequently, we consider granular porous media with homogeneous and heterogeneous wettability conditions. We investigate the influence of capillary and viscous forces as well as wettability conditions on the interfacial dynamics, displacement efficiency, phase trapping phenomenon, and interfacial instabilities. For the heterogeneous wettability conditions, we consider granular media with mixed-wet conditions as well as fractional (patterned) wettability conditions. Finally, at the end of this dissertation, we present a physics-constrained super-resolution framework that can super-resolve numerical simulation data in both space and time. We test the robustness of our proposed super-resolution framework for super-resolving simulation data obtained for a turbulent flow case of Rayleigh-Bénard convection problem as well as a case of two-phase flow interfacial dynamics in porous media for a subsurface reservoir.

Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems

Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems
Author : Anonim
Publisher : Unknown
Release Date : 2002
Category : Composite materials
Total pages :442
GET BOOK

Multiscale and Multiresolution Approaches in Turbulence

Multiscale and Multiresolution Approaches in Turbulence
Author : Pierre Sagaut
Publisher : World Scientific
Release Date : 2013
Category : Science
Total pages :448
GET BOOK

The book aims to provide the reader with an updated general presentation of multiscale/multiresolution approaches in turbulent flow simulations. All modern approaches (LES, hybrid RANS/LES, DES, SAS) are discussed and recast in a global comprehensive framework. Both theoretical features and practical implementation details are addressed. Some full scale applications are described, to provide the reader with relevant guidelines to facilitate a future use of these methods.

High Performance Scientific And Engineering Computing

High Performance Scientific And Engineering Computing
Author : Michael Breuer,Franz Durst,Christoph Zenger
Publisher : Springer Science & Business Media
Release Date : 2012-12-06
Category : Computers
Total pages :408
GET BOOK

In Douglas Adams' book 'Hitchhiker's Guide to the Galaxy', hyper-intelligent beings reached a point in their existence where they wanted to understand the purpose of their own existence and the universe. They built a supercomputer, called Deep Thought, and upon completion, they asked it for the answer to the ultimate question of life, the universe and everything else. The computer worked for several millennia on the answers to all these questions. When the day arrived for hyper-intelligent beings the to receive the answer, they were stunned, shocked and disappointed to hear that the answer was simply 42. The still open questions to scientists and engineers are typically much sim pler and consequently the answers are more reasonable. Furthermore, because human beings are too impatient and not ready to wait for such a long pe riod, high-performance computing techniques have been developed, leading to much faster answers. Based on these developments in the last two decades, scientific and engineering computing has evolved to a key technology which plays an important role in determining, or at least shaping, future research and development activities in many branches of industry. Development work has been going on all over the world resulting in numerical methods that are now available for simulations that were not foreseeable some years ago. However, these days the availability of supercomputers with Teraflop perfor mance supports extensive computations with technical relevance. A new age of engineering has started.

Annual Research Briefs ...

Annual Research Briefs ...
Author : Center for Turbulence Research (U.S.)
Publisher : Unknown
Release Date : 2011
Category : Turbulence
Total pages :129
GET BOOK

Data Analysis for Direct Numerical Simulations of Turbulent Combustion

Data Analysis for Direct Numerical Simulations of Turbulent Combustion
Author : Heinz Pitsch,Antonio Attili
Publisher : Springer Nature
Release Date : 2020-05-28
Category : Mathematics
Total pages :292
GET BOOK

This book presents methodologies for analysing large data sets produced by the direct numerical simulation (DNS) of turbulence and combustion. It describes the development of models that can be used to analyse large eddy simulations, and highlights both the most common techniques and newly emerging ones. The chapters, written by internationally respected experts, invite readers to consider DNS of turbulence and combustion from a formal, data-driven standpoint, rather than one led by experience and intuition. This perspective allows readers to recognise the shortcomings of existing models, with the ultimate goal of quantifying and reducing model-based uncertainty. In addition, recent advances in machine learning and statistical inferences offer new insights on the interpretation of DNS data. The book will especially benefit graduate-level students and researchers in mechanical and aerospace engineering, e.g. those with an interest in general fluid mechanics, applied mathematics, and the environmental and atmospheric sciences.

Multiscale Modeling in Biomechanics and Mechanobiology

Multiscale Modeling in Biomechanics and Mechanobiology
Author : Suvranu De,Wonmuk Hwang,Ellen Kuhl
Publisher : Springer
Release Date : 2014-10-10
Category : Technology & Engineering
Total pages :286
GET BOOK

Presenting a state-of-the-art overview of theoretical and computational models that link characteristic biomechanical phenomena, this book provides guidelines and examples for creating multiscale models in representative systems and organisms. It develops the reader's understanding of and intuition for multiscale phenomena in biomechanics and mechanobiology, and introduces a mathematical framework and computational techniques paramount to creating predictive multiscale models. Biomechanics involves the study of the interactions of physical forces with biological systems at all scales – including molecular, cellular, tissue and organ scales. The emerging field of mechanobiology focuses on the way that cells produce and respond to mechanical forces – bridging the science of mechanics with the disciplines of genetics and molecular biology. Linking disparate spatial and temporal scales using computational techniques is emerging as a key concept in investigating some of the complex problems underlying these disciplines. Providing an invaluable field manual for graduate students and researchers of theoretical and computational modelling in biology, this book is also intended for readers interested in biomedical engineering, applied mechanics and mathematical biology.

Multi-scale Simulation of Composite Materials

Multi-scale Simulation of Composite Materials
Author : Stefan Diebels,Sergej Rjasanow
Publisher : Springer
Release Date : 2019-02-01
Category : Science
Total pages :178
GET BOOK

Due to their high stiffness and strength and their good processing properties short fibre reinforced thermoplastics are well-established construction materials. Up to now, simulation of engineering parts consisting of short fibre reinforced thermoplastics has often been based on macroscopic phenomenological models, but deformations, damage and failure of composite materials strongly depend on their microstructure. The typical modes of failure of short fibre thermoplastics enriched with glass fibres are matrix failure, rupture of fibres and delamination, and pure macroscopic consideration is not sufficient to predict those effects. The typical predictive phenomenological models are complex and only available for very special failures. A quantitative prediction on how failure will change depending on the content and orientation of the fibres is generally not possible, and the direct involvement of the above effects in a numerical simulation requires multi-scale modelling. One the one hand, this makes it possible to take into account the properties of the matrix material and the fibre material, the microstructure of the composite in terms of fibre content, fibre orientation and shape as well as the properties of the interface between fibres and matrix. On the other hand, the multi-scale approach links these local properties to the global behaviour and forms the basis for the dimensioning and design of engineering components. Furthermore, multi-scale numerical simulations are required to allow efficient solution of the models when investigating three-dimensional problems of dimensioning engineering parts. Bringing together mathematical modelling, materials mechanics, numerical methods and experimental engineering, this book provides a unique overview of multi-scale modelling approaches, multi-scale simulations and experimental investigations of short fibre reinforced thermoplastics. The first chapters focus on two principal subjects: the mathematical and mechanical models governing composite properties and damage description. The subsequent chapters present numerical algorithms based on the Finite Element Method and the Boundary Element Method, both of which make explicit use of the composite’s microstructure. Further, the results of the numerical simulations are shown and compared to experimental results. Lastly, the book investigates deformation and failure of composite materials experimentally, explaining the applied methods and presenting the results for different volume fractions of fibres. This book is a valuable resource for applied mathematics, theoretical and experimental mechanical engineers as well as engineers in industry dealing with modelling and simulation of short fibre reinforced composites.

Multiscale Modelling of Soft Matter

Multiscale Modelling of Soft Matter
Author : Philip Earis,Madelaine Chapman
Publisher : Royal Society of Chemistry
Release Date : 2010
Category : Technology & Engineering
Total pages :492
GET BOOK

This volume focuses on multiscale modelling: crossing the boundaries from atomistic studies of relatively small systems, to tackle larger systems where the properties of interest can only be studied at longer distances and longer time-scales. Many of the ideas of multiscale modelling cross traditional boundaries and this meeting brought together scientists from several different fields of modelling to discuss state of the art modelling of membranes, colloids, polymers and proteins. The following themes were included in the discussion: - Polymers: including microphase separation and self-assembly - Colloids: including the prediction of phases and phase diagrams - Mesophases: including liquid crystals, novel phases, self-assembled structures and the links between molecular structure and bulk properties - Membranes: including collective processes in lipid and surfactant systems - Methodology for multiscale simulations: including methods for moving between scales and for bridging different time and length scales

Studying Turbulence Using Numerical Simulation Databases

Studying Turbulence Using Numerical Simulation Databases
Author : Anonim
Publisher : Unknown
Release Date : 2002
Category :
Total pages :129
GET BOOK

Numerical Simulations of Coupled Problems in Engineering

Numerical Simulations of Coupled Problems in Engineering
Author : Sergio R. Idelsohn
Publisher : Springer
Release Date : 2014-05-09
Category : Technology & Engineering
Total pages :422
GET BOOK

This book presents and discusses mathematical models, numerical methods and computational techniques used for solving coupled problems in science and engineering. It takes a step forward in the formulation and solution of real-life problems with a multidisciplinary vision, accounting for all of the complex couplings involved in the physical description. Simulation of multifaceted physics problems is a common task in applied research and industry. Often a suitable solver is built by connecting together several single-aspect solvers into a network. In this book, research in various fields was selected for consideration: adaptive methodology for multi-physics solvers, multi-physics phenomena and coupled-field solutions, leading to computationally intensive structural analysis. The strategies which are used to keep these problems computationally affordable are of special interest, and make this an essential book.

An Improved Multiscale Model for Dilute Turbulent Gas Particle Flows Based on the Equilibration of Energy Concept

An Improved Multiscale Model for Dilute Turbulent Gas Particle Flows Based on the Equilibration of Energy Concept
Author : Ying Xu
Publisher : Unknown
Release Date : 2004
Category :
Total pages :134
GET BOOK

Many particle-laden flows in engineering applications involve turbulent gas flows. Modeling multiphase turbulent flows is an important research topic with applications in fluidized beds and particle conveying. A predictive multiphase turbulence model can help CFD codes to be more useful for engineering applications, such as the scale-up in the design of circulating fluidized combustor and coal gasifications. It is reasonable to expect that multiphase turbulence models should at least satisfy some basic modeling and performance criteria and give reasonable predictions for the canonical problems in dilute particle-laden turbulent flows. In this research, a comparative assessment of predictions from Simonin and Ahmadi's turbulence models is performed with direct numerical simulation (DNS) for two canonical problems in particle-laden turbulent flows. Based on the comparative assessment, some criteria and the areas for model improvement are identified: (i) model for interphase TKE transfer, especially the time scale of interphase TKE transfer, and (ii) correct prediction of TKE evolution with variation of particle Stokes number. Some deficiencies that are identified in the Simonin and Ahmadi models limit the applicability. A new multiphase turbulence model, the Equilibration of Energy Model (EEM), is proposed in this work. In EEM, a multiscale interaction time scale is proposed to account for the interaction of a particle with a range of eddy sizes. EEM shows good agreement with the DNS results for particle-laden istropic turbulence. For particle-laden homogeneous shear flows, model predictions from EEM can be further improved if the dissipation rate in fluid phase is modeled with more accuracy. This new time scale is incorporated in the interphase TKE transfer terms of the Simonin and Ahmadi models. For canonical problems in particle-laden turbulent flows, this time scale improves the predictions from these two models. Although EEM is a simple model, it has a clear physical interpretation and gives reasonable predictions for two canonical problems in particle-laden turbulent flows. It can be a useful engineering tool for CFD calculations of gas-solid two phase flows.

Ames Research Center Research and Technology 2000

Ames Research Center Research and Technology 2000
Author : Anonim
Publisher : Unknown
Release Date : 2002
Category :
Total pages :197
GET BOOK