On the visual growth of a turbulent mixing layer

1980 ◽  
Vol 96 (3) ◽  
pp. 447-460 ◽  
Author(s):  
J. Jimenez
Keyword(s):  
Turbulent Mixing ◽  
Mixing Layer ◽  
Vortex Sheet ◽  
Spreading Rate ◽  
Layer Growth ◽  
Mixing Layers ◽  
Turbulent Mixing Layer

Two models are discussed to account for the motion of the concentration interface in turbulent mixing layers. In the first one the interface is treated as a vortex sheet and its roll-up is studied. It is argued that this situation represents only the first stages of layer growth and another model is studied in detail in which a row of vortex cores entrains an essentially passive concentration interface with no vorticity. Both models give values of the spreading rate in approximate agreement with observations, and their relation is discussed.

Effects of heat release on the large-scale structure in turbulent mixing layers

1989 ◽  
Vol 199 ◽  
pp. 297-332 ◽  
Author(s):  
P. A. Mcmurtry ◽  
J. J. Riley ◽  
R. W. Metcalfe
Keyword(s):  
Heat Release ◽  
Turbulent Mixing ◽  
Large Scale ◽  
Mixing Layer ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Mixing Layers ◽  
Turbulent Mixing Layer ◽  
Large Scale Structures ◽  
Scale Structures

The effects of chemical heat release on the large-scale structure in a chemically reacting, turbulent mixing layer are investigated using direct numerical simulations. Three-dimensional, time-dependent simulations are performed for a binary, single-step chemical reaction occurring across a temporally developing turbulent mixing layer. It is found that moderate heat release slows the development of the large-scale structures and shifts their wavelengths to larger scales. The resulting entrainment of reactants is reduced, decreasing the overall chemical product formation rate. The simulation results are interpreted in terms of turbulence energetics, vorticity dynamics, and stability theory. The baroclinic torque and thermal expansion in the mixing layer produce changes in the flame vortex structure that result in more diffuse vortices than in the constant-density case, resulting in lower rotation rates of the large-scale structures. Previously unexplained anomalies observed in the mean velocity profiles of reacting jets and mixing layers are shown to result from vorticity generation by baroclinic torques.

The interaction between the mean flow and coherent structures in turbulent mixing layers

1994 ◽  
Vol 260 ◽  
pp. 81-94 ◽  
Author(s):  
J. Cohen ◽  
B. Marasli ◽  
V. Levinski
Keyword(s):  
Velocity Profile ◽  
Coherent Structures ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Mean Flow ◽  
Mean Velocity ◽  
Turbulent Mixing Layer ◽  
Self Similar ◽  
The Mean

The nonlinear interaction between the mean flow and a coherent disturbance in a two-dimensional turbulent mixing layer is addressed. Based on considerations from stability theory, previous experimental results, in particular the modification of the mean velocity profile, the peculiar growth of the forced shear-layer thickness and the spatial growth of the disturbance amplitude, are explained. A model that assumes a quasi-parallel mean flow having a self-similar mean velocity profile is developed. The model is capable of predicting the downstream evolution of turbulent mixing layers subjected to external excitations.

Validation Case Study: Prediction of Compressible Turbulent Mixing Layer Growth Rate

AIAA Journal ◽  
2006 ◽  
Vol 44 (7) ◽  
pp. 1488-1497 ◽  
Author(s):  
M. F. Barone ◽  
W. L. Oberkampf ◽  
F. G. Blottner
Keyword(s):  
Growth Rate ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Layer Growth ◽  
Turbulent Mixing Layer ◽  
Layer Growth Rate

scholarly journals Mixing layers in flows in star forming regions

1997 ◽  
Vol 178 ◽  
pp. 89-102 ◽  
Author(s):  
A. C. Raga ◽  
J. Cantó
Keyword(s):  
Turbulent Mixing ◽  
Chemical Structure ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Molecular Gas ◽  
Turbulent Mixing Layer ◽  
Star Forming ◽  
Star Forming Regions ◽  
Surrounding Environment ◽  
Model Equations

There are now many observations of high velocity, molecular emission associated with outflows from young stars. This emission might come from molecules that are formed in the outflowing material, or from entrained, ambient molecular gas. The present paper explores the latter possibility, describing the efforts that have been made to model the “lateral entrainment” that occurs in the turbulent mixing layer formed along the edges of a jet-like flow (or, equivalently, at any interface between a fast moving flow and the surrounding environment). A simple, analytic approach based on model equations is used to provide a qualitative picture of the dynamical, thermal and chemical structure of such a turbulent mixing layer. Finally, a review of the efforts up to date of modelling the dynamics and chemistry of turbulent mixing layers is presented.

Wavelet analysis of shearless turbulent mixing layer

2021 ◽  
Vol 33 (2) ◽  
pp. 025109
Author(s):  
T. Matsushima ◽  
K. Nagata ◽  
T. Watanabe
Keyword(s):  
Wavelet Analysis ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Turbulent Mixing Layer
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