Book ChapterDOI
Some Effects of Density Variations in Turbulent Flows with Pressure Fluctuations
A. A. Burluka,V. A. Frost,V. Meytlis +2 more
- pp 543-551
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TLDR
In this article, the balance equations for conditionally averaged velocity and fluctuation intensity are obtained and these values have been shown to depend upon density and turbulent Schmidt number for uniform homogeneous turbulence, even when there is no pressure wave.Abstract:
To analyse the possible effects of density variations, which are induced by combustion and heat exchange processes, on turbulent flows with varying pressure field it is proposed to employ the balance equation for conditional probability density function (PDF) of velocity at concentration value fixed. The latter is derived from the governing set of Langevin’s type equations which replaces the commonly used Navier-tocks and molecular diffusion equations set. By using it the balance equations for conditionally averaged velocity and fluctuation intensity are obtained and these values have been shown to depend upon density and turbulent Schmidt number for uniform homogeneous turbulence, even when there is no pressure wave. And, naturally, lighter gas volumes have greater velocity fluctuation intensity.read more
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Book ChapterDOI
Conditional Velocity Statistics in Turbulent Jets
TL;DR: In this article, the authors studied the combined statistics of the velocity and scalar fields, in particular the conditional averages of velocity, which arise in turbulent combustion models based on probability density functions (pdfs).
References
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Journal ArticleDOI
Recent developments in dea : the mathematical programming approach to frontier analysis
TL;DR: In this paper, the authors discuss the mathematical programming approach to frontier estimation known as Data Envelopment Analysis (DEA) and examine the effect of model orientation on the efficient frontier.
Journal ArticleDOI
Temperature fluctuations and scales in grid-generated turbulence
TL;DR: In this paper, the authors studied the mixing of a passive scalar in nearly isotropic turbulence, experiments have been made in isotropically mixed thermal fields with thermal mesh sizes Mθ equal to the momentum mesh size M, larger than M (obtained by heating only alternate rods of the turbulence generating grid), and smaller than M.
Journal ArticleDOI
Calculations of premixed turbulent flames by PDF methods
M. S. Anand,Stephen B. Pope +1 more
TL;DR: In this article, the authors used probability density function (pdf) methods to simulate premixed turbulent flames and solved a modeled transport equation for the joint pdf of velocity and reaction progress variable by a Monte Carlo method.
BookDOI
Turbulent reactive flows
R. Borghi,S.N.B. Murthy +1 more
TL;DR: In this paper, the topology of large-scale structures in Turbulent Reacting Flows has been measured and the results of the measurements of the velocity probability density in a Spark Ignition Engine have been presented.
Journal ArticleDOI
The pdf Approach to Turbulent Flow
TL;DR: In this paper, the authors provide a detailed discussion of the theory and application of probability density function (pdf) methods, which provide a complete statistical description of turbulent flow fields at a single point or a finite number of points.