Author: Publisher:
ISBN:
Category : Combustion chambers
Languages : ka
Pages : 70
Book Description
Modeling of Turbulent Swirling Flows
Author: Modeling of Turbulent Swirling Flows
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722646417
Category :
Languages : en
Pages : 56
Book Description
Aircraft engine combustors generally involve turbulent swirling flows in order to enhance fuel-air mixing and flame stabilization. It has long been recognized that eddy viscosity turbulence models are unable to appropriately model swirling flows. Therefore, it has been suggested that, for the modeling of these flows, a second order closure scheme should be considered because of its ability in the modeling of rotational and curvature effects. However, this scheme will require solution of many complicated second moment transport equations (six Reynolds stresses plus other scalar fluxes and variances), which is a difficult task for any CFD implementations. Also, this scheme will require a large amount of computer resources for a general combustor swirling flow. This report is devoted to the development of a cubic Reynolds stress-strain model for turbulent swirling flows, and was inspired by the work of Launder's group at UMIST. Using this type of model, one only needs to solve two turbulence equations, one for the turbulent kinetic energy k and the other for the dissipation rate epsilon. The cubic model developed in this report is based on a general Reynolds stress-strain relationship. Two flows have been chosen for model evaluation. One is a fully developed rotating pipe flow, and the other is a more complex flow with swirl and recirculation. Shih, Tsan-Hsing and Zhu, Jiang and Liou, William and Chen, Kuo-Huey and Liu, Nan-Suey and Lumley, John L. Glenn Research Center...
Modeling of Turbulent Swirling Flows
Author: Modeling and Measurement of Turbulent Swirling Flows Through Abrupt Expansions
Author: G. P. NeitzelPublisher:
ISBN:
Category :
Languages : en
Pages : 114
Book Description
Contents: A study of sudden expansion pipe flow using an algebraic-stress model of turbulence; Comment on 'The flowfield in a suddenly enlarged combustion chamber'; Turbulent flow prediction in a sudden axisymmetric expansion; Heat transfer to turbulent swirling flow through a sudden axisymmetric expansion; Measurements in turbulent swirling flow through an abrupt axisymmetric expansion. The first three papers describe numerical predictions of the flowfield; The next describes experimental measurements of local convective heat transfer on the tube walls downstream of expansion; and the last describes detailed mean and fluctuating flowfield measurements both upstream and downstream of the expansion including precessing vortex core phenomena.
Coarse Grained Simulation and Turbulent Mixing
Author: Fenando F. GrinsteinPublisher: Cambridge University Press
ISBN: 1107137047
Category : Science
Languages : en
Pages : 481
Book Description
Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.
Simulation and Modeling of Turbulent Flows
Author: Thomas B. GatskiPublisher: Oxford University Press
ISBN: 0195355563
Category : Science
Languages : en
Pages : 329
Book Description
This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.
Turbulent Flows
Author: G. BiswasPublisher: CRC Press
ISBN: 9780849310140
Category : Technology & Engineering
Languages : en
Pages : 478
Book Description
This book allows readers to tackle the challenges of turbulent flow problems with confidence. It covers the fundamentals of turbulence, various modeling approaches, and experimental studies. The fundamentals section includes isotropic turbulence and anistropic turbulence, turbulent flow dynamics, free shear layers, turbulent boundary layers and plumes. The modeling section focuses on topics such as eddy viscosity models, standard K-E Models, Direct Numerical Stimulation, Large Eddy Simulation, and their applications. The measurement of turbulent fluctuations experiments in isothermal and stratified turbulent flows are explored in the experimental methods section. Special topics include modeling of near wall turbulent flows, compressible turbulent flows, and more.
Modelling of Turbulent Swirling Flows
Author: Lee Nicholas JonesTurbulent Flows
Author: Jean PiquetPublisher: Springer Science & Business Media
ISBN: 3662035596
Category : Technology & Engineering
Languages : en
Pages : 767
Book Description
obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.
An Evaluation of Numerical Calculations in Turbulent Swirling Flows
Author: Liang-jy LeuPublisher:
ISBN:
Category : Boundary layer turbulence
Languages : en
Pages : 186
Book Description