Mean and Turbulence Characteristics of a Class of Three-Dimensional Wall Jets—Part 2: Turbulence Characteristics

1991 ◽  
Vol 113 (4) ◽  
pp. 629-634 ◽  
Author(s):  
G. Padmanabham ◽  
B. H. Lakshmana Gowda
Keyword(s):  
Three Dimensional ◽  
Flow Characteristics ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Mean Flow ◽  
Wall Jets ◽  
Turbulence Characteristics ◽  
Turbulent Wall Jets ◽  
The Mean ◽  
Turbulent Wall

The mean flow characteristics of three-dimensional, incompressible, isothermal turbulent wall jets generated from orifices having the shapes of various segments of a circle are presented in Part 1 of this paper. In this part, the turbulence characteristics are presented. Turbulence quantities measured include normal stresses and Reynolds shear stresses in the characteristic-decay and in the radial-decay regions of the wall jets investigated. These results are compared with those available for two-dimensional and three-dimensional wall jets. The presence of counter-gradient regions and the feature of “energy reveral” are discussed.

Characteristics of 3D Turbulent Wall Jets and Offset Jets With Small Offset Ratios

2009 ◽  
Author(s):  
M. Agelinchaab ◽  
M. F. Tachie
Keyword(s):  
Three Dimensional ◽  
Symmetry Plane ◽  
Shear Stresses ◽  
Wall Jets ◽  
Particle Image Velocimetry Technique ◽  
Image Velocimetry ◽  
Turbulent Wall Jets ◽  
The Mean ◽  
Turbulent Wall ◽  
Proper Orthogonal

This paper reports an experimental study of turbulent three-dimensional generic wall jets and offset jets. The jets were created from a long circular pipe. A particle image velocimetry technique was used to conduct velocity measurements in the symmetry plane of the jet. From these measurements, the salient features of the flows are reported in terms of the mean velocities, turbulence intensities and Reynolds shear stresses. The energy spectra and profiles of reconstructed turbulence intensities and Reynolds shear stresses from low order proper orthogonal decomposition modes are also reported.

Three-Dimensional Turbulent Wall Jets

2009 ◽  
Author(s):  
M. Agelinchaab ◽  
M. F. Tachie
Keyword(s):  
Reynolds Number ◽  
Turbulence Intensity ◽  
Large Scale ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Wall Jets ◽  
Turbulent Statistics ◽  
Turbulent Wall Jets ◽  
The Mean ◽  
Turbulent Wall

Particle image velocimetry (PIV) measurements were carried out on generic three-dimensional turbulent wall jets. The wall jets were created from a long circular pipe at Reynolds number based on the jet exit velocity (Uj) and inside diameter of pipe (d) of Rej = Ujd/v = 7680 to 19500. The profiles of the mean velocities, turbulence intensities and Reynolds shear stresses in the streamwise/wall-normal and streamwise/lateral planes are presented. Consistent with previous results, the profiles of the mean velocities and turbulent statistics are independent of Reynolds number. The mean velocity attained self-similarity before the turbulence quantities. The decay rate and spread rates obtained in the present study fall in between the values reported in previous studies. The contours of the two-point velocity correlations in the inner region of the 3D wall jet are qualitatively similar to those reported in boundary layer studies. The results from proper orthogonal analysis revealed that large scale structures are largely responsible for the distribution of the streamwise turbulence intensity and Reynolds shear stresses than the distribution of the wall-normal turbulence intensity.

Mean and Turbulence Characteristics of a Class of Three-Dimensional Wall Jets—Part 1: Mean Flow Characteristics

1991 ◽  
Vol 113 (4) ◽  
pp. 620-628 ◽  
Author(s):  
G. Padmanabham ◽  
B. H. Lakshmana Gowda
Keyword(s):  
Three Dimensional ◽  
Flow Characteristics ◽  
Experimental Investigations ◽  
Wall Jet ◽  
Mean Flow ◽  
Wall Jets ◽  
Mean Velocity ◽  
Turbulence Characteristics ◽  
Turbulent Wall ◽  
And Behavior

This paper reports experimental investigations on mean and turbulence characteristics of three-dimensional, incompressible, isothermal turbulent wall jets generated from orifices having the shapes of various segments of a circle. In Part 1, the mean flow characteristics are presented. The turbulence characteristics are presented in Part 2. The influence of the geometry on the characteristic decay region of the wall jet is brought out and the differences with other shapes are discussed. Mean velocity profiles both in the longitudinal and lateral planes are measured and compared with some of the theoretical profiles. Wall jet expansion rates and behavior of skin-friction are discussed. The influence of the geometry of the orifice on the various wall jet properties is presented and discussed. Particularly the differences between this class of geometry and rectangular geometries are critically discussed.

Coherent structures and dominant frequencies in a turbulent three-dimensional diffuser

2012 ◽  
Vol 699 ◽  
pp. 320-351 ◽  
Author(s):  
Johan Malm ◽  
Philipp Schlatter ◽  
Dan S. Henningson
Keyword(s):  
Coherent Structures ◽  
Large Scale ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Low Frequency ◽  
Bulk Velocity ◽  
Time Signal ◽  
Mean Flow ◽  
The Mean ◽  
Dominant Frequencies

AbstractDominant frequencies and coherent structures are investigated in a turbulent, three-dimensional and separated diffuser flow at $\mathit{Re}= 10\hspace{0.167em} 000$ (based on bulk velocity and inflow-duct height), where mean flow characteristics were first studied experimentally by Cherry, Elkins and Eaton (Intl J. Heat Fluid Flow, vol. 29, 2008, pp. 803–811) and later numerically by Ohlsson et al. (J. Fluid Mech., vol. 650, 2010, pp. 307–318). Coherent structures are educed by proper orthogonal decomposition (POD) of the flow, which together with time probes located in the flow domain are used to extract frequency information. The present study shows that the flow contains multiple phenomena, well separated in frequency space. Dominant large-scale frequencies in a narrow band $\mathit{St}\equiv fh/ {u}_{b} \in [0. 0092, 0. 014] $ (where $h$ is the inflow-duct height and ${u}_{b} $ is the bulk velocity), yielding time periods ${T}^{\ensuremath{\ast} } = T{u}_{b} / h\in [70, 110] $, are deduced from the time signal probes in the upper separated part of the diffuser. The associated structures identified by the POD are large streaks arising from a sinusoidal oscillating motion in the diffuser. Their individual contributions to the total kinetic energy, dominated by the mean flow, are, however, small. The reason for the oscillating movement in this low-frequency range is concluded to be the confinement of the flow in this particular geometric set-up in combination with the high Reynolds number and the large separated zone on the top diffuser wall. Based on this analysis, it is shown that the bulk of the streamwise root mean square (r.m.s.) value arises due to large-scale motion, which in turn can explain the appearance of two or more peaks in the streamwise r.m.s. value. The weak secondary flow present in the inflow duct is shown to survive into the diffuser, where it experiences an imbalance with respect to the upper expanding corners, thereby giving rise to the asymmetry of the mean separated region in the diffuser.

scholarly journals Erratum for “Three-Dimensional Turbulent Wall Jets”

1974 ◽  
Vol 100 (12) ◽  
pp. 1849-1849
Author(s):  
Nallamuthu Rajaratnam ◽  
Bidya Sagar Pani
Keyword(s):  
Three Dimensional ◽  
Wall Jets ◽  
Turbulent Wall Jets ◽  
Turbulent Wall

Three-Dimensional Turbulent Wall Jets

1974 ◽  
Vol 100 (1) ◽  
pp. 69-83 ◽  
Author(s):  
Nallamuthu Rajaratnam ◽  
Bidya Sagar Pani
Keyword(s):  
Three Dimensional ◽  
Wall Jets ◽  
Turbulent Wall Jets ◽  
Turbulent Wall
Sign in / Sign up

Export Citation Format

Share Document