The Influence of Variable Density on Turbulent Wall Jet: A Numerical Comparative Study

The first objective of this numerical research is to help understand the influence of variable density on the structure of turbulence, through the study of a wall jet, and to validate our results with those of the experimental study of A. Soudani. The source of density variation is the mixture between two different non-reactive fluids, with a fixed temperature and pressure. A mass weighted averaging for different variables is applied to the calculation, using ANSYS FLUENT 15.0 commercial software. The principal experience consists of injecting tangentially and alternatively near the wall a gas (air-helium) different from the external flow, through a slot of height 3mm between two plane walls. Such a process permits to provoke an important density difference. The study reaches the conclusion that turbulence is strong, with a slight increase of velocity near the wall and an evident diminution of skin friction, in the case of light fluid injection. The second aim is to estimate the Kolmogorov and large eddies’ scales to construct LES grid to access instant variables in experience.

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A Two∼Dimensional Wall Jet with Suction

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-1972-0029 ◽

1972 ◽

Vol 1 (4) ◽

pp. 182-188

Author(s):

T.B. Hedley ◽

J.F. Keffer

Keyword(s):

Viscous Sublayer ◽

Transport Processes ◽

Wall Jet ◽

Two Dimensional ◽

Mean Flow ◽

Law Of The Wall ◽

Free Jet ◽

The Mean ◽

Turbulent Wall ◽

Large Eddies

The mean flow field of a two-dimensional turbulent wall jet which encounters a uniform suction is examined. A marked increase in wall shear stress was observed for all suction levels as the jet moved into the suction zone. When the suction level is moderate a viscous sublayer exists next to the surface. The dominance of the flow by the free jet motion however prevents any law-of-the-wall representation for the adjacent turbulent region and a velocity defect model is found to be more satisfactory. One can interpret this lack of an extensive equilibrium layer to mean that the transport processes are controlled by the action of the large eddies over almost the entire wall jet zone, with or without suction.

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Mixing of a Turbulent Wall-Jet into a Free Stream

Transactions of the American Society of Civil Engineers ◽

10.1061/taceat.0008666 ◽

1963 ◽

Vol 128 (1) ◽

pp. 1055-1073

Author(s):

S. Eskinazi ◽

V. Kruka

Keyword(s):

Free Stream ◽

Wall Jet ◽

Turbulent Wall

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Plane Turbulent Free Jet and Wall Jet

Journal of the Royal Aeronautical Society ◽

10.1017/s000192400005507x ◽

1967 ◽

Vol 71 (680) ◽

pp. 585-587 ◽

Cited By ~ 1

Author(s):

N. Rajaratnam ◽

K. Subramanya

Keyword(s):

Velocity Distribution ◽

Smooth Boundary ◽

Wall Jet ◽

Length Scales ◽

Ambient Environment ◽

Free Jet ◽

Turbulent Wall

The aim of this note is to compare the plane turbulent free jet diffusing in an infinite stagnant ambient environment with the corresponding plane turbulent wall jet on a smooth boundary regarding the three important characteristics, namely the velocity distribution and the variation of the velocity and length scales, in the region of developed flow.

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Low-Order Velocity Estimation and Acoustic Noise Generation by a Turbulent Wall Jet

AIAA Journal ◽

10.2514/1.j057042 ◽

2018 ◽

Vol 56 (11) ◽

pp. 4331-4347 ◽

Cited By ~ 2

Author(s):

Adam Nickels ◽

Lawrence Ukeiley ◽

Robert Reger ◽

Louis Cattafesta

Keyword(s):

Acoustic Noise ◽

Velocity Estimation ◽

Wall Jet ◽

Noise Generation ◽

Turbulent Wall ◽

Low Order

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Effects of inertia and stratification in incompressible ideal fluids: pressure imbalances by rigid confinement

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.218 ◽

2013 ◽

Vol 726 ◽

pp. 404-438 ◽

Cited By ~ 7

Author(s):

R. Camassa ◽

S. Chen ◽

G. Falqui ◽

G. Ortenzi ◽

M. Pedroni

Keyword(s):

Euler Equations ◽

Initial Conditions ◽

Numerical Algorithms ◽

Wave Dispersion ◽

Variable Density ◽

Density Variation ◽

Fluid Inertia ◽

Time Dynamics ◽

Long Wave ◽

Set Up

AbstractConsequences of density stratification are studied for an ideal (Euler) incompressible fluid, confined to move under gravity between rigid lids but otherwise free to move along horizontal directions. Initial conditions that generate horizontal pressure imbalances in a laterally unbounded domain are examined. The aim is to show analytically the existence of classes of initial data for which total horizontal momentum evolves in time, even though only vertical forces act on the fluid in this set-up. A simple class of such initial conditions, leading to momentum evolution, is identified by systematic asymptotic expansions of the governing inhomogeneous Euler equations in the small-density-variation limit. These results for Euler equations are compared and confirmed with long-wave asymptotic models, which can handle arbitrary density variations and provide closed-form mathematical expressions for limiting cases. In particular, the role of wave dispersion arising from the fluid inertia is captured by the long-wave models, even for short-time dynamics emanating from initial conditions outside the models’ asymptotic range of validity. These results are compared with direct numerical simulations for variable-density Euler fluids, which further validate the numerical algorithms and the analysis.

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Parameters governing the turbulent wall jet in an external stream

AIAA Journal ◽

10.2514/3.11695 ◽

1993 ◽

Vol 31 (5) ◽

pp. 848-853 ◽

Cited By ~ 23

Author(s):

M. D. Zhou ◽

I. Wygnanski

Keyword(s):

Wall Jet ◽

Turbulent Wall ◽

External Stream

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Simulation and Modeling of Flow in a Gas Compressor

Journal of Applied Mathematics ◽

10.1155/2015/682469 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7

Author(s):

Anna Avramenko ◽

Alexey Frolov ◽

Jari Hämäläinen

Keyword(s):

Steady State ◽

Mass Flow ◽

Gas Flow ◽

Simulation Method ◽

High Mass ◽

Ansys Fluent ◽

Flow Rates ◽

Mass Flow Rates ◽

Low Mass ◽

Flow Through

The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

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