Characterisation of Turbulent Duct Flows
Characterisation of Turbulent Duct Flows

Author: Bayode Owolabi

Publisher: Springer

Published: 2019-05-31

Total Pages: 165

ISBN-13: 303019745X

DOWNLOAD EBOOK

This book presents several new findings in the field of turbulent duct flows, which are important for a range of industrial applications. It presents both high-quality experiments and cutting-edge numerical simulations, providing a level of insight and rigour rarely found in PhD theses. The scientific advancements concern the effect of the Earth’s rotation on large duct flows, the experimental confirmation of marginal turbulence in a pressure-driven square duct flow (previously only predicted in simulations), the identification of similar marginal turbulence in wall-driven flows using simulations (for the first time by any means) and, on a separate but related topic, a comprehensive experimental study on the phenomenon of drag reduction via polymer additives in turbulent duct flows. In turn, the work on drag reduction resulted in a correlation that provides a quantitative prediction of drag reduction based on a single, measurable material property of the polymer solution, regardless of the flow geometry or concentration. The first correlation of its kind, it represents an important advancement from both a scientific and practical perspective.

Fluid Flow Phenomena
Fluid Flow Phenomena

Author: Paolo Orlandi

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 369

ISBN-13: 9401142815

DOWNLOAD EBOOK

This book deals with the simulation of the incompressible Navier-Stokes equations for laminar and turbulent flows. The book is limited to explaining and employing the finite difference method. It furnishes a large number of source codes which permit to play with the Navier-Stokes equations and to understand the complex physics related to fluid mechanics. Numerical simulations are useful tools to understand the complexity of the flows, which often is difficult to derive from laboratory experiments. This book, then, can be very useful to scholars doing laboratory experiments, since they often do not have extra time to study the large variety of numerical methods; furthermore they cannot spend more time in transferring one of the methods into a computer language. By means of numerical simulations, for example, insights into the vorticity field can be obtained which are difficult to obtain by measurements. This book can be used by graduate as well as undergraduate students while reading books on theoretical fluid mechanics; it teaches how to simulate the dynamics of flow fields on personal computers. This will provide a better way of understanding the theory. Two chapters on Large Eddy Simulations have been included, since this is a methodology that in the near future will allow more universal turbulence models for practical applications. The direct simulation of the Navier-Stokes equations (DNS) is simple by finite-differences, that are satisfactory to reproduce the dynamics of turbulent flows. A large part of the book is devoted to the study of homogeneous and wall turbulent flows. In the second chapter the elementary concept of finite difference is given to solve parabolic and elliptical partial differential equations. In successive chapters the 1D, 2D, and 3D Navier-Stokes equations are solved in Cartesian and cylindrical coordinates. Finally, Large Eddy Simulations are performed to check the importance of the subgrid scale models. Results for turbulent and laminar flows are discussed, with particular emphasis on vortex dynamics. This volume will be of interest to graduate students and researchers wanting to compare experiments and numerical simulations, and to workers in the mechanical and aeronautic industries.

Transition and Turbulence
Transition and Turbulence

Author: Richard E. Meyer

Publisher: Academic Press

Published: 2014-05-10

Total Pages: 257

ISBN-13: 1483264599

DOWNLOAD EBOOK

Mathematics Research Center Symposia and Advanced Seminar Series: Transition and Turbulence covers the lectures presented at the Symposium on Transition and Turbulence in Fluids, held in Madison, Wisconsin on October 13-15, 1980 under the auspices of the Mathematics Research Center of the University of Wisconsin-Madison. The book focuses on the relation between transition and turbulence in fluids and the importance of this relation for the understanding of many real fluid motions. The selection first elaborates on transition in flow between rotating concentric cylinders, observations in the Taylor experiment, and transition to turbulence in thermal convection with and without rotation. Discussions focus on low aspect ratio convection layers, random convection in a rotating layer, unsteady flows at high Reynolds numbers, transition to oscillatory motion, and experimental observations. The text then tackles instability and turbulence in jets, instability and transition in pipes and channels, and transition to turbulence in boundary layers. The book ponders on coherent structures in turbulence; interactions between large-scale coherent structures and fine-grained turbulence in free shear flows; and vortex interactions and coherent structures in turbulence. Topics include atomic and molecular representations, vortices in uniform strain, vortex pairs, numerical computations applied to a simple problem, agglomeration of large-scale structures and subharmonic formation, retrieving phase information, and dynamical equations. The selection is highly recommended for researchers interested in pursuing further studies on transition and turbulence.

Mathematical Models and Integration Methods
Mathematical Models and Integration Methods

Author: Oleg V. Kaptsov

Publisher: Walter de Gruyter GmbH & Co KG

Published: 2024-09-23

Total Pages: 180

ISBN-13: 3111546667

DOWNLOAD EBOOK

The book compiles works presented at a seminar aiming to attract global experts in differential equations, mathematical modeling, and integration methods. It covers classical and contemporary integration techniques for partial differential equations, including Monge and Darboux's approaches and their extensions. Additionally, it introduces a novel theoretical model for plane turbulent flows, presents gravitational equations derived from the principle of least action, and explores symmetry-preserving conservative finite-difference schemes for hydrodynamic-type equations. Analytical solutions for Maxwell's equations in incompressible viscoelastic mediums are examined, alongside theoretical-group analysis of wake mathematical models and reduction to ordinary differential equations. The book also delves into special classes of two-dimensional ideal fluid motion and advancements in discrete orthogonal polynomial theory, showcasing rapid decay properties near interval boundaries. In conclusion, this comprehensive collection is indispensable for researchers and practitioners in applied mathematics, fluid dynamics, and computational modeling, providing valuable insights into cutting-edge methods and solutions in the field.