Direct Simulation of Scalar Mixing in a Compressible Mixing Layer

1995 ◽  
pp. 340-345 ◽  
Author(s):  
K. H. Luo ◽  
N. D. Sandham
Keyword(s):  
Mixing Layer ◽  
Direct Simulation ◽  
Scalar Mixing ◽  
Compressible Mixing Layer

Compressible mixing layer - Linear theory and direct simulation

AIAA Journal ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 618-624 ◽  
Author(s):  
N. D. Sandham ◽  
W. C. Reynolds
Keyword(s):  
Linear Theory ◽  
Mixing Layer ◽  
Direct Simulation ◽  
Compressible Mixing Layer

Large-Scale Structures in a Compressible Mixing Layer over a Cavity

AIAA Journal ◽  
2003 ◽  
Vol 41 (12) ◽  
Author(s):  
Jonathan Poggie ◽  
Alexander J. Smits
Keyword(s):  
Large Scale ◽  
Mixing Layer ◽  
Compressible Mixing Layer ◽  
Large Scale Structures ◽  
Scale Structures

Reaction in a scalar mixing layer

1991 ◽  
Vol 233 ◽  
pp. 211-242 ◽  
Author(s):  
R. W. Bilger ◽  
L. R. Saetran ◽  
L. V. Krishnamoorthy
Keyword(s):  
Chemical Reaction ◽  
Mixing Layer ◽  
Reacting Flow ◽  
Scalar Mixing ◽  
Scalar Theory ◽  
Thermal Mixing ◽  
Fast Chemistry ◽  
The Mean ◽  
Reactive Scalars ◽  
Made In

Reaction in a scalar mixing layer in grid-generated turbulence is studied experimentally by doping half of the flow with nitric oxide and the other half with ozone. The flow conditions and concentrations are such that the chemical reaction is passive and the flow and chemical timescales are of the same order. Conserved scalar theory for such flows is outlined and further developed; it is used as a basis for presentation of the experimental results. Continuous measurements of concentration are limited in their spatial and temporal resolution but capture sufficient of their spectra for adequate second-order correlations to be made. Two components of velocity have been measured simultaneously with hot-wire anemometry. Conserved scalar mixing results, deduced from reacting and non-reacting measurements of concentration, show the independence of concentration level and concentration ratio expected for passive reacting flow. The results are subject to several limitations due to the necessary experimental compromises, but they agree generally with measurements made in thermal mixing layers. Reactive scalar statistics are consistent with the realizability constraints obtainable from conserved scalar theory where such constraints apply, and otherwise are generally found to lie between the conserved scalar theory limits for frozen and very fast chemistry. It is suggested that Toor's (1969) closure for the mean chemical reaction rate could be improved by interpolating between the frozen and equilibrium values for the covariance. The turbulent fluxes of the reactive scalars are found to approximately obey the gradient model but the value of the diffusivity is found to depend on the Damköhler number.

scholarly journals Inviscid spatial stability of a compressible mixing layer. Part 3. Effect of thermodynamics

1991 ◽  
Vol 224 ◽  
pp. 159-175 ◽  
Author(s):  
T. L. Jackson ◽  
C. E. Grosch
Keyword(s):  
Prandtl Number ◽  
Mixing Layer ◽  
Mean Flow ◽  
Temperature Relation ◽  
Compressible Mixing Layer ◽  
Spatial Stability ◽  
Mean Temperature ◽  
The Mean ◽  
The Difference ◽  
The Stability

We report the results of a comprehensive comparative study of the inviscid spatial stability of a parallel compressible mixing layer using various models for the mean flow. The models are (i) the hyperbolic tangent profile for the mean speed and the Crocco relation for the mean temperature, with the Chapman viscosity–temperature relation and a Prandtl number of one; (ii) the Lock profile for the mean speed and the Crocco relation for the mean temperature, with the Chapman viscosity-temperature relation and a Prandtl number of one; and (iii) the similarity solution for the coupled velocity and temperature equations using the Sutherland viscosity–temperature relation and arbitrary but constant Prandtl number. The purpose of this study was to determine the sensitivity of the stability characteristics of the compressible mixing layer to the assumed thermodynamic properties of the fluid. It is shown that the qualitative features of the stability characteristics are quite similar for all models but that there are quantitative differences resulting from the difference in the thermodynamic models. In particular, we show that the stability characteristics are sensitive to the value of the Prandtl number and to a particular value of the temperature ratio across the mixing layer.

An experimental investigation of the effects of compressibility on a turbulent reacting mixing layer

1998 ◽  
Vol 356 ◽  
pp. 25-64 ◽  
Author(s):  
M. F. MILLER ◽  
C. T. BOWMAN ◽  
M. G. MUNGAL
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Structural Changes ◽  
Density Ratio ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Unexpected Result ◽  
Entrainment Ratio ◽  
Plan View ◽  
Compressible Mixing Layer

Experiments were conducted to investigate the effect of compressibility on turbulent reacting mixing layers with moderate heat release. Side- and plan-view visualizations of the reacting mixing layers, which were formed between a high-speed high-temperature vitiated-air stream and a low-speed ambient-temperature hydrogen stream, were obtained using a combined OH/acetone planar laser-induced fluorescence imaging technique. The instantaneous images of OH provide two-dimensional maps of the regions of combustion, and similar images of acetone, which was seeded into the fuel stream, provide maps of the regions of unburned fuel. Two low-compressibility (Mc=0.32, 0.35) reacting mixing layers with differing density ratios and one high-compressibility (Mc=0.70) reacting mixing layer were studied. Higher average acetone signals were measured in the compressible mixing layer than in its low-compressibility counterpart (i.e. same density ratio), indicating a lower entrainment ratio. Additionally, the compressible mixing layer had slightly wider regions of OH and 50% higher OH signals, which was an unexpected result since lowering the entrainment ratio had the opposite effect at low compressibilities. The large-scale structural changes induced by compressibility are believed to be primarily responsible for the difference in the behaviour of the high- and low-compressibility reacting mixing layers. It is proposed that the coexistence of broad regions of OH and high acetone signals is a manifestation of a more biased distribution of mixture compositions in the compressible mixing layer. Other mechanisms through which compressibility can affect the combustion are discussed.

Compressible Mixing Layer Experiments for CFD Validation

2019 ◽  
Author(s):  
J C. Dutton ◽  
Greg S. Elliott ◽  
Kevin Kim
Keyword(s):  
Mixing Layer ◽  
Cfd Validation ◽  
Compressible Mixing Layer
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