Variable Density Fluid Turbulence

Author : P. Chassaing
Publisher : Springer Science & Business Media
ISBN 13 : 9401700753
Total Pages : 387 pages
Book Rating : 4.57/5 ( download)

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Download or read book Variable Density Fluid Turbulence written by P. Chassaing and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part aims at providing the physical and theoretical framework of the analysis of density variations in fully turbulent flows. Its scope is deliberately educational. In the second part, basic data on dynamical and scalar properties of variable density turbulent flows are presented and discussed, based on experimental data and/or results from direct numerical simulations. This part is rather concerned with a research audience. The last part is more directly devoted to an engineering audience and deals with prediction methods for turbulent flows of variable density fluid. Both first and second order, single point modeling are discussed, with special emphasis on the capability to include specific variable density / compressibility effects.

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Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.41/5 ( download)

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Download or read book The Dynamics of Variable-density Turbulence written by and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field, is in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 1283 grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations. In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For the case of buoyancy-generated turbulence, variable-density departures from the Boussinesq approximation are studied. The results of the buoyancy-generated turbulence are compared with variable-density model predictions. Both a one-point (engineering) model and a two-point (spectral) model are tested against the numerical data. Some deficiencies in these variable-density models are discussed and modifications are suggested.

Author : Louis Fulachier
Publisher : Springer Science & Business Media
ISBN 13 : 9401154740
Total Pages : 372 pages
Book Rating : 4.41/5 ( download)

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Download or read book IUTAM Symposium on Variable Density Low-Speed Turbulent Flows written by Louis Fulachier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: The General Assembly of the International Union of Theoretical and Applied Mechanics in its meeting on August 28, 1994, selected for 1996 only four Mechanics Symposia, of which ours is the only one related to Fluid Mechanics: Variable Density Low Speed Turbulent Flows. This IUTAM Symposium, organized by the Institut de Recherche sur les Phenomenes Hors Equilibre (Marseille), is the logical continuation of the meetings previously organized or co-organized - on the French or European level, such as Euromech 237, Marseille, 1988 - by the same research group ofMarseille. This meeting focused specifically on the structure of turbulent flows in which density varies strongly : the effect of this variation on the velocity and scalar fields is in no sense negligible. We were mainly concerned with low-speed flows subjected to strong local changes of density as a consequence of heat or mass transfer or of chemical reactions. Compressible turbulent flows - such a!" supersonic ones - were also considered in order to underline their similarities to and their differences from low-speed variable density flows.

Author : Gordon C. K. Yeh
Publisher :
ISBN 13 :
Total Pages : 44 pages
Book Rating : 4.49/5 ( download)

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Download or read book A Two-Equation Turbulence Model for a Dispersed Two-Phased Flow with Variable Density Fluid and Constant Density Particles written by Gordon C. K. Yeh and published by . This book was released on 1985 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two equation turbulence model has been developed for predicting a dispersed two phase flow with variable density fluid and constant density particles. The two equations describe the conservation of turbulence kinetic energy and its dissipation rate for the fluid. They have been derived rigorously from the momentum equations of the carrier fluid in the two phase flow. Closure of the time mean equations is achieved by modeling the turbulent correlations up to third order. The new model eliminates the need to simulate in an ad hoc manner the effects of the dispersed phase on turbulent structure in situations where the compressibility of the fluid must be taken into account.

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ISBN 13 :
Total Pages : pages
Book Rating : 4.07/5 ( download)

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Download or read book Probability Density Function Method for Variable-density Pressure-gradient-driven Turbulence and Mixing written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Probability density function (PDF) methods are extended to variable-density pressure-gradient-driven turbulence. We apply the new method to compute the joint PDF of density and velocity in a non-premixed binary mixture of different-density molecularly mixing fluids under gravity. The full time-evolution of the joint PDF is captured in the highly non-equilibrium flow: starting from a quiescent state, transitioning to fully developed turbulence and finally dissipated by molecular diffusion. High-Atwood-number effects (as distinguished from the Boussinesq case) are accounted for: both hydrodynamic turbulence and material mixing are treated at arbitrary density ratios, with the specific volume, mass flux and all their correlations in closed form. An extension of the generalized Langevin model, originally developed for the Lagrangian fluid particle velocity in constant-density shear-driven turbulence, is constructed for variable-density pressure-gradient-driven flows. The persistent small-scale anisotropy, a fundamentally 'non-Kolmogorovian' feature of flows under external acceleration forces, is captured by a tensorial diffusion term based on the external body force. The material mixing model for the fluid density, an active scalar, is developed based on the beta distribution. The beta-PDF is shown to be capable of capturing the mixing asymmetry and that it can accurately represent the density through transition, in fully developed turbulence and in the decay process. The joint model for hydrodynamics and active material mixing yields a time-accurate evolution of the turbulent kinetic energy and Reynolds stress anisotropy without resorting to gradient diffusion hypotheses, and represents the mixing state by the density PDF itself, eliminating the need for dubious mixing measures. Direct numerical simulations of the homogeneous Rayleigh-Taylor instability are used for model validation.

Author : Ramis Örlü
Publisher : Springer Nature
ISBN 13 : 3030221962
Total Pages : 339 pages
Book Rating : 4.66/5 ( download)

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Download or read book Progress in Turbulence VIII written by Ramis Örlü and published by Springer Nature. This book was released on 2019-08-27 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects the edited and reviewed contributions presented in the 8th iTi Conference on Turbulence, held in Bertinoro, Italy, in September 2018. In keeping with the spirit of the conference, the book was produced afterwards, so that the authors had the opportunity to incorporate comments and discussions raised during the event. The respective contributions, which address both fundamental and applied aspects of turbulence, have been structured according to the following main topics: I TheoryII Wall-bounded flowsIII Simulations and modellingIV ExperimentsV Miscellaneous topicsVI Wind energy/div

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Publisher :
ISBN 13 :
Total Pages : 39 pages
Book Rating : 4.07/5 ( download)

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Download or read book Turbulence Transport Equations for Variable-density Turbulence and Their Relationship to Two-field Models written by and published by . This book was released on with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study gives an updated account of our current ability to describe multimaterial compressible turbulent flows by means of a one-point transport model. Evolution equations are developed for a number of second-order correlations of turbulent data, and approximations of the gradient type are applied to additional correlations to close the system of equations. The principal fields of interest are the one- point Reynolds tensor for variable-density flow, the turbulent energy dissipation rate, and correlations for density-velocity and density- density fluctuations. This single-field description of turbulent flows is compared in some detail to two-field flow equations for nonturbulent, highly dispersed flow with separate variables for each field. This comparison suggests means for improved modeling of some correlations not subjected to evolution equations.

Author : Ching Jen Chen
Publisher : CRC Press
ISBN 13 : 9781560324058
Total Pages : 312 pages
Book Rating : 4.58/5 ( download)

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Download or read book Fundamentals Of Turbulence Modelling written by Ching Jen Chen and published by CRC Press. This book was released on 1997-12-01 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on the second-order turbulence-closure model and its applications to engineering problems. Topics include turbulent motion and the averaging process, near-wall turbulence, applications of turbulence models, and turbulent buoyant flows.

Author : Donald Leon Sandoval
Publisher :
ISBN 13 :
Total Pages : 482 pages
Book Rating : 4.33/5 ( download)

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Download or read book The Dynamics of Variable-density Turbulence written by Donald Leon Sandoval and published by . This book was released on 1995 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Author : James Liburdy
Publisher :
ISBN 13 : 9781955101103
Total Pages : pages
Book Rating : 4.08/5 ( download)

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Download or read book Intermediate Fluid Mechanics written by James Liburdy and published by . This book was released on 2021-09-16 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: