Author: G. Grötzbach
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
Book Description
Modelling Turbulent Dissipation Correlations for Rayleigh-Bénard Convection Based on Two-point Correlation Technique Andinvariant Theory
Modelling Turbulent Dissipation Correlations for Rayleigh Bénard Convection Based on Two-point Correlation Technique and Invariant Theory
Author: Qiao-yan Ye
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
Book Description
Statistics and Scaling in Turbulent Rayleigh-Bénard Convection
Author: Emily S.C. Ching
Publisher: Springer
ISBN: 9789814560221
Category : Technology & Engineering
Languages : en
Pages : 0
Book Description
This Brief addresses two issues of interest of turbulent Rayleigh-Bénard convection. The first issue is the characterization and understanding of the statistics of the velocity and temperature fluctuations in the system. The second issue is the revelation and understanding of the nature of the scaling behavior of the velocity temperature structure functions. The problem under the Oberbeck-Boussinesq approximation is formulated. The statistical tools, including probability density functions (PDF) and conditional statistics, for studying fluctuations are introduced, and implicit PDF formulae for fluctuations obeying certain statistical symmetries are derived. Applications of these PDF formulae to study the fluctuations in turbulent Rayleigh-Bénard convection are then discussed. The phenomenology of the different types of scaling behavior: the Bolgiano-Obhukov scaling behavior when buoyancy effects are significant and the Kolmogorov-Obukhov-Corrsin scaling behavior when they are not, is introduced. A crossover between the two types of scaling behavior is expected to occur at the Bolgiano length scale above which buoyancy is important. The experimental observations are reviewed. In the central region of the convective cell, the Kolmogorov-Obukhov-Corrsin scaling behavior has been observed. On the other hand, the Bolgiano-Obukhov scaling remains elusive only until recently. By studying the dependence of the conditional temperature structure functions on the locally averaged thermal dissipation rate, evidence for the Bolgiano-Obukhov scaling has recently been found near the bottom plate. The different behaviors observed in the two regions could be attributed to the different size of the Bolgiano scale. What physics determines the relative size of the Bolgiano scale remains to be understood. The Brief is concluded by a discussion of these outstanding issues.
Publisher: Springer
ISBN: 9789814560221
Category : Technology & Engineering
Languages : en
Pages : 0
Book Description
This Brief addresses two issues of interest of turbulent Rayleigh-Bénard convection. The first issue is the characterization and understanding of the statistics of the velocity and temperature fluctuations in the system. The second issue is the revelation and understanding of the nature of the scaling behavior of the velocity temperature structure functions. The problem under the Oberbeck-Boussinesq approximation is formulated. The statistical tools, including probability density functions (PDF) and conditional statistics, for studying fluctuations are introduced, and implicit PDF formulae for fluctuations obeying certain statistical symmetries are derived. Applications of these PDF formulae to study the fluctuations in turbulent Rayleigh-Bénard convection are then discussed. The phenomenology of the different types of scaling behavior: the Bolgiano-Obhukov scaling behavior when buoyancy effects are significant and the Kolmogorov-Obukhov-Corrsin scaling behavior when they are not, is introduced. A crossover between the two types of scaling behavior is expected to occur at the Bolgiano length scale above which buoyancy is important. The experimental observations are reviewed. In the central region of the convective cell, the Kolmogorov-Obukhov-Corrsin scaling behavior has been observed. On the other hand, the Bolgiano-Obukhov scaling remains elusive only until recently. By studying the dependence of the conditional temperature structure functions on the locally averaged thermal dissipation rate, evidence for the Bolgiano-Obukhov scaling has recently been found near the bottom plate. The different behaviors observed in the two regions could be attributed to the different size of the Bolgiano scale. What physics determines the relative size of the Bolgiano scale remains to be understood. The Brief is concluded by a discussion of these outstanding issues.
New Perspectives in Turbulence
Author: L. Sirovich
Publisher:
ISBN:
Category : Turbulence
Languages : en
Pages : 392
Book Description
Publisher:
ISBN:
Category : Turbulence
Languages : en
Pages : 392
Book Description
Two-point Closure Study of Covariance Budgets for Turbulent Rayleigh-Benard Convection
Author: William Paul Dannevik
Publisher:
ISBN:
Category : Convection (Meteorology)
Languages : en
Pages : 165
Book Description
Publisher:
ISBN:
Category : Convection (Meteorology)
Languages : en
Pages : 165
Book Description
Simulation of the Turbulent Rayleigh-Benard Problem Using a Spectral/finite Difference Technique
Author: Institute for Computer Applications in Science and Engineering
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
Book Description
International Aerospace Abstracts
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 988
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 988
Book Description
A theoretical and experimental study of two-layer Rayleigh-Benard convection
Author: Adam Gregory Henly
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages :
Book Description
On Turbulent Rayleigh-Bénard Convection in a Two-phase Binary Gas Mixture
Author: Florian Winkel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In this thesis an attempt is made to generate cloud patterns in a laboratory scale experiment. A two-phase binary gas mixture is employed as a physical model system. The fluid mixture is composed of a condensable gas which forms a liquid and a vapor phase and a noncondensable gas which serves as a background or carrier gas. The fluid mixture is confined between a bottom and a top plate. If the fluid mixture is exposed to a constant temperature difference, two intriguing phenomena can be observed. First a film condensation sets in at the cold top plate that results in the formation of a very ...
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In this thesis an attempt is made to generate cloud patterns in a laboratory scale experiment. A two-phase binary gas mixture is employed as a physical model system. The fluid mixture is composed of a condensable gas which forms a liquid and a vapor phase and a noncondensable gas which serves as a background or carrier gas. The fluid mixture is confined between a bottom and a top plate. If the fluid mixture is exposed to a constant temperature difference, two intriguing phenomena can be observed. First a film condensation sets in at the cold top plate that results in the formation of a very ...
Two-point Correlation Equations for Variable Density Turbulence
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 62
Book Description
A complete set of two-point correlation equations for variable-density turbulence is derived to consistent order in mass-weighted variables (Favre averaging). The derivation is based on a two-point generalization of the Reynolds stress tensor. The equations are transformed with respect to the separation between the two points to Fourier space. The correlation equations, as well as the Fourier-transformed equations, provide insights that are unavailable in the one-point equations. The derivation of spectral closures is significantly more complicated than that of constant-density closures or one-point variable-density closures due to the complex nature of isotropic scalar-vector correlation functions for nonsolenoidal fields. Several necessary constraints for the correlation functions are presented. In addition, a simple spectral model that satisfies these constraints is presented for illustrative purposes, and a discussion of the two-point correlations and their relationship to the corresponding correlations arising in one-point derivations is provided.
Publisher:
ISBN:
Category :
Languages : en
Pages : 62
Book Description
A complete set of two-point correlation equations for variable-density turbulence is derived to consistent order in mass-weighted variables (Favre averaging). The derivation is based on a two-point generalization of the Reynolds stress tensor. The equations are transformed with respect to the separation between the two points to Fourier space. The correlation equations, as well as the Fourier-transformed equations, provide insights that are unavailable in the one-point equations. The derivation of spectral closures is significantly more complicated than that of constant-density closures or one-point variable-density closures due to the complex nature of isotropic scalar-vector correlation functions for nonsolenoidal fields. Several necessary constraints for the correlation functions are presented. In addition, a simple spectral model that satisfies these constraints is presented for illustrative purposes, and a discussion of the two-point correlations and their relationship to the corresponding correlations arising in one-point derivations is provided.