Compressibility effects due to turbulent fluctuations

1996 ◽  
Vol 57 (3-4) ◽  
pp. 165-194 ◽  
Author(s):  
R. Friedrich ◽  
F. P. Bertolotti
Keyword(s):  
Turbulent Fluctuations ◽  
Compressibility Effects

Optimization of the Three-Dimensional Flow Path in the Scroll-Nozzle System of a Radial Inflow Turbine

1984 ◽  
Vol 106 (2) ◽  
pp. 511-515 ◽  
Author(s):  
E. A. Baskharone
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Three Dimensional Flow ◽  
Multiply Connected ◽  
Dimensional Flow ◽  
Nozzle Configuration ◽  
Flow Domain ◽  
Radial Inflow Turbine ◽  
Compressibility Effects

A three-dimensional inviscid flow analysis in the combined scroll-nozzle system of a radial inflow turbine is presented. The coupling of the two turbine components leads to a geometrically complicated, multiply-connected flow domain. Nevertheless, this coupling accounts for the mutual effects of both elements on the three-dimensional flow pattern throughout the entire system. Compressibility effects are treated for an accurate prediction of the nozzle performance. Different geometrical configurations of both the scroll passage and the nozzle region are investigated for optimum performance. The results corresponding to a sample scroll-nozzle configuration are verified by experimental measurements.

Turbulent fluctuations in the viscous wall region for Newtonian and drag reducing fluids

1977 ◽  
Vol 20 (10) ◽  
pp. S112 ◽  
Author(s):  
Thomas J. Hanratty ◽  
Larry G. Chorn ◽  
Dimitrios T. Hatziavramidis
Keyword(s):  
Wall Region ◽  
Turbulent Fluctuations

A General Closure Model for the Time-Averaged Radiative Transfer Equation in Turbulent Flows

2010 ◽  
Author(s):  
Pedro J. Coelho
Keyword(s):  
Radiative Transfer ◽  
Turbulent Flows ◽  
Radiation Intensity ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Mixture Fraction ◽  
Joint Probability ◽  
Turbulent Fluctuations ◽  
Proposed Model ◽  
Local Properties

The time-averaged form of the radiative transfer equation (RTE) includes emission and absorption correlations that need to be modeled. There is no general formulation to estimate the absorption coefficient-radiation intensity correlation, which is generally neglected (optically thin fluctuation approximation–OTFA). Here, a model to compute this correlation, as well as the other correlations in the time-averaged form of the RTE, is described. The formulation is based on the solution of two additional differential equations. The unclosed correlations in these equations are estimated assuming that the joint probability density function (pdf) of the radiation intensity and mixture fraction is a two-dimensional clipped Gaussian distribution. The model is applied to a turbulent jet diffusion flame, and a preliminary assessment of the model is reported. It is shown that fluctuations of the radiation intensity, caused by turbulence, imply the existence of a correlation between the radiation intensity and local properties. The assumption of the shape of the joint pdf of mixture fraction and radiation intensity yields satisfactory predictions if the turbulent fluctuations are moderate, but becomes inaccurate near the flame edge where turbulent fluctuations are very large. Nevertheless, the present results suggest that the proposed model may yield better predictions than the OTFA.

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