scholarly journals TURBULENT DIFFUSION OF A THREE-DIMENSIONAL WALL JET : lST REPORT, MEAN AND TURBULENT CHARACTERISTICS OF VELOCITY AND TEMPERATURE FIELD

1982 ◽  
Vol 25 (200) ◽  
pp. 173-181 ◽  
Author(s):  
TORU KOSO ◽  
HIDEO OHASHI
Keyword(s):  
Temperature Field ◽  
Turbulent Diffusion ◽  
Three Dimensional ◽  
Wall Jet ◽  
Turbulent Characteristics

Mean and Turbulence Characteristics of Three-Dimensional Wall Jet on Convex Cylindrical Surfaces

1999 ◽  
Vol 121 (3) ◽  
pp. 596-604
Author(s):  
B. H. Lakshmana Gowda ◽  
V. S. B. Durbha
Keyword(s):  
Plane Surface ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Spanwise Direction ◽  
Shear Stresses ◽  
Wall Jet ◽  
Curvature Effects ◽  
Turbulent Characteristics ◽  
Curvature Parameter ◽  
The Mean

The influence of convex curvature on the mean and turbulent characteristics of three-dimensional wall jet generated from a circular orifice geometry is reported in this paper. Mild, moderate, and strong curvature are considered. Detailed results on a plane surface are also obtained for comparison purposes. Among the mean properties, the decay rate of maximum velocity and the growth of length scales are significantly altered due to curvature effects. The turbulent components, both turbulent normal and shear stresses, show an increase with curvature parameter in a direction normal to the curved surfaces; however, there is very little change in the spanwise direction.

Numerical Study of the Mean and Filtered Characteristics of Turbulent Jets Impinging on Convex and Flat Surfaces Using LES

2012 ◽  
Author(s):  
Adra Benhacine ◽  
Zoubir Nemouchi ◽  
Lyes Khezzar ◽  
Nabil Kharoua
Keyword(s):  
Convex Surface ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbulent Jets ◽  
Scale Model ◽  
Wall Jet ◽  
Potential Core ◽  
Flat Surfaces ◽  
Free Jet ◽  
Eddy Simulation

A numerical study of a turbulent plane jet impinging on a convex surface and on a flat surface is presented, using the large eddy simulation approach and the Smagorinski-Lilly sub-grid-scale model. The effects of the wall curvature on the unsteady filtered, and the steady mean, parameters characterizing the dynamics of the wall jet are addressed in particular. In the free jet upstream of the impingement region, significant and fairly ordered velocity fluctuations, that are not turbulent in nature, are observed inside the potential core. Kelvin-Helmholtz instabilities in the shear layer between the jet and the surrounding air are detected in the form of wavy sheets of vorticity. Rolled up vortices are detached from these sheets in a more or less periodic manner, evolving into distorted three dimensional structures. Along the wall jet the Coanda effect causes a marked suction along the convex surface compared with the flat one. As a result, relatively important tangential velocities and a stretching of sporadic streamwise vortices are observed, leading to friction coefficient values on the curved wall higher than those on the flat wall.

scholarly journals The study of three-dimensional temperature field distribution reconstruction using ultrasonic thermometry

AIP Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 075007 ◽  
Author(s):  
Ruixi Jia ◽  
Qingyu Xiong ◽  
Kai Wang ◽  
Lijie Wang ◽  
Guangyu Xu ◽  
...  
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Temperature Field Distribution

Investigation of Turbulent Mixing in a Macro-Scale Multi-Inlet Vortex Nanoprecipitation Reactor by Stereoscopic-PIV

2014 ◽  
Author(s):  
Zhenping Liu ◽  
James C. Hill ◽  
Rodney O. Fox ◽  
Michael G. Olsen
Keyword(s):  
Reynolds Number ◽  
Turbulent Mixing ◽  
Three Dimensional ◽  
Stereoscopic Particle Image Velocimetry ◽  
Vortex Center ◽  
Mean Velocity ◽  
Vortex Model ◽  
Functional Nanoparticles ◽  
Turbulent Characteristics ◽  
Macro Scale

Flash Nanoprecipitation (FNP) is a technique to produce monodisperse functional nanoparticles through rapidly mixing a saturated solution and a non-solvent. Multi-inlet vortex reactors (MIVR) have been effectively applied to FNP due to their ability to provide both rapid mixing and the flexibility of inlet flow conditions. Until recently, only micro-scale MIVRs have been demonstrated to be effective in FNP. A scaled-up MIVR could potentially generate large quantities of functional nanoparticles, giving FNP wider applicability in the industry. In the present research, turbulent mixing inside a scaled-up, macro-scale MIVR was measured by stereoscopic particle image velocimetry (SPIV). Reynolds number of this reactor is defined based on the bulk inlet velocity, ranging from 3290 to 8225. It is the first time that the three-dimensional velocity field of a MIVR was experimentally measured. The influence of Reynolds number on mean velocity becomes more linear as Reynolds number increases. An analytical vortex model was proposed to well describe the mean velocity profile. The turbulent characteristics such as turbulent kinematic energy and Reynolds stress are also presented. The wandering motion of vortex center was found to have a significant contribution to the turbulent kinetic energy of flow near the center area.

The Lid-Driven Cavity Flow: A Synthesis of Qualitative and Quantitative Observations

1984 ◽  
Vol 106 (4) ◽  
pp. 390-398 ◽  
Author(s):  
J. R. Koseff ◽  
R. L. Street
Keyword(s):  
Heat Flux ◽  
Flow Visualization ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Lower Boundary ◽  
Thymol Blue ◽  
Width Ratio ◽  
Cavity Depth ◽  
Driven Cavity ◽  
Turbulent Characteristics

A synthesis of observations of flow in a three-dimensional lid-driven cavity is presented through the use of flow visualization pictures and velocity and heat flux measurements. The ratio of the cavity depth to width used was 1:1 and the span to width ratio was 3:1. Flow visualization was accomplished using the thymol blue technique and by rheoscopic liquid illuminated by laser-light sheets. Velocity measurements were made using a two-component laser-Doppler-anemometer and the heat flux on the lower boundary of the cavity was measured using flush mounted sensors. The flow is three-dimensional and is weaker at the symmetry plane than that predicted by accurate two-dimensional numerical simulations. Local three-dimensional features, such as corner vortices in the end-wall regions and longitudinal Taylor-Go¨rtler-like vortices, are significant influences on the flow. The flow is unsteady in the region of the downstream secondary eddy at higher Reynolds numbers (Re) and exhibits turbulent characteristics in this region at Re = 10,000.

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