A Method of Measuring the Three-Dimensional Mean Flow and Turbulence Quantities Inside a Rotating Turbo-machinery Passage

1976 ◽  
Vol 98 (2) ◽  
pp. 137-144 ◽  
Author(s):  
C. A. Gorton ◽  
B. Lakshminarayana
Keyword(s):  
Turbulence Intensity ◽  
Three Dimensional ◽  
Hot Wire ◽  
Mean Flow ◽  
Mean Velocity ◽  
Hot Wire Anemometry ◽  
Turbo Machinery ◽  
Velocity Turbulence

A method of measuring the three-dimensional components of mean velocity and turbulence quantities within a rotating turbomachinery passage is developed through the use of hot wire anemometry techniques. Equations are derived which, when solved simultaneously and in conjunction with the data obtained from the hot wire anemometer measurements, will provide values for the radial, axial and tangential components of mean velocity, turbulence intensity and turbulence stress within the rotating turbomachinery passage. A three-bladed rocket pump inducer model, operating in air, was used in the experimentation. The method is very accurate and provides very useful information on the characteristics of the flow inside rotor passages hitherto unexplored.

Experimental investigation of jets in a crossflow

1984 ◽  
Vol 138 ◽  
pp. 93-127 ◽  
Author(s):  
J. Andreopoulos ◽  
W. Rodi
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Shear Stresses ◽  
Hot Wire ◽  
Mean Flow ◽  
Mean Velocity ◽  
Turbulent Kinetic Energy Equation

The paper reports on measurements in the flow generated by a jet issuing from a circular outlet in a wall into a cross-stream along this wall. For the jet-to-crossflow velocity ratios R of 0.5, 1 and 2, the mean and fluctuating velocity components were measured with a three-sensor hot-wire probe. The hot-wire signals were evaluated to yield the three mean-velocity components, the turbulent kinetic energy, the three turbulent shear stresses and, in the case of R = 0.5, the terms in the turbulent-kinetic-energy equation. The results give a quantitative picture of the complex three-dimensional mean flow and turbulence field, and the various phenomena as well as their dependence on the velocity ratio R are discussed in detail.

A Swirling Round Turbulent Jet: 1—Mean-Flow Measurements

1962 ◽  
Vol 29 (4) ◽  
pp. 615-625 ◽  
Author(s):  
W. G. Rose
Keyword(s):  
Turbulence Intensity ◽  
Turbulent Pipe Flow ◽  
Hot Wire ◽  
Mean Flow ◽  
Rapid Decay ◽  
Mean Velocity ◽  
Rapid Reduction ◽  
Flow Measurements ◽  
Mean Values ◽  
Swirling Jet

A swirling jet of air is generated for this work by flow issuing from a rotating pipe into a reservoir of motionless air. At the pipe discharge, the flow is roughly a fully developed, turbulent pipe flow in solid-body rotation. Owing to the very rapid decay of the swirl, measurements are confined to a region extending from the pipe discharge out to a distance of 15 pipe diameters. Mean-velocity magnitudes and mean directions are the primary results; in addition, one turbulence intensity component is included. All velocities and intensities were measured with a constant-temperature hot-wire anemometer having a linearized response, and all mean values were determined by electronic integration. Contrasted with the nonswirling jet, the jet with swirl spreads at a larger angle, entrains reservoir fluid more rapidly, and consequently displays a more rapid reduction of mean-velocity and growth of turbulence intensity. In its gross features, at large distances from the orifice, the measured swirling jet agrees with the predictions of “weak-swirl” analyses.

Techniques for Aerodynamic and Turbulence Measurements in Turbomachinery Rotors

1981 ◽  
Vol 103 (2) ◽  
pp. 374-392 ◽  
Author(s):  
B. Lakshminarayana
Keyword(s):  
Data Transmission ◽  
Three Dimensional ◽  
Surface Measurement ◽  
Blade Surface ◽  
Flow Data ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Mean Velocity ◽  
Velocity Turbulence ◽  
Probe Measurements

The objective of this paper is to review the techniques employed for the measurement of flow in turbomachinery rotors. Only nonoptical techniques are included. Measurement of the following properties are covered: three-dimensional mean velocity, turbulence intensity and Reynolds stresses, static and stagnation pressures, and blade surface measurement. Both the conventional as well as the hot-wire/film techniques, including both the rotating- and the stationary-probe measurements, are reviewed. A brief description of various rotating-probe traverse mechanisms and rotor flow data transmission systems in use is also included.

Measurements with a pulsed-wire and a hot-wire anemometer in the highly turbulent wake of a normal flat plate

1976 ◽  
Vol 77 (3) ◽  
pp. 473-497 ◽  
Author(s):  
L. J. S. Bradbury
Keyword(s):  
Turbulent Flow ◽  
Flat Plate ◽  
Flow Direction ◽  
Operating Conditions ◽  
Turbulent Intensity ◽  
Hot Wire ◽  
Mean Flow ◽  
Mean Velocity ◽  
The Mean ◽  
Better Than

This paper describes an investigation into the response of both the pulsed-wire anemometer and the hot-wire anemometer in a highly turbulent flow. The first part of the paper is concerned with a theoretical study of some aspects of the response of these instruments in a highly turbulent flow. It is shown that, under normal operating conditions, the pulsed-wire anemometer should give mean velocity and longitudinal turbulent intensity estimates to an accuracy of better than 10% without any restriction on turbulence level. However, to attain this accuracy in measurements of turbulent intensities normal to the mean flow direction, there is a lower limit on the turbulent intensity of about 50%. An analysis is then carried out of the behaviour of the hot-wire anemometer in a highly turbulent flow. It is found that the large errors that are known to develop are very sensitive to the precise structure of the turbulence, so that even qualitative use of hot-wire data in such flows is not feasible. Some brief comments on the possibility of improving the accuracy of the hot-wire anemometer are then given.The second half of the paper describes some comparative measurements in the highly turbulent flow immediately downstream of a normal flat plate. It is shown that, although it is not possible to interpret the hot-wire results on their own, it is possible to calculate the hot-wire response with a surprising degree of accuracy using the results from the pulsed-wire anemometer. This provides a rather indirect but none the less welcome check on the accuracy of the pulsed-wire results, which, in this very highly turbulent flow, have a certain interest in their own right.

The Influence of Aspect Ratio on Incompressible, Turbulent Flows From Rectangular Slots

1980 ◽  
Vol 31 (4) ◽  
pp. 285-305 ◽  
Author(s):  
G.F. Marsters ◽  
J. Fotheringham
Keyword(s):  
Aspect Ratio ◽  
Turbulent Flows ◽  
Turbulence Intensity ◽  
Three Dimensional ◽  
Thin Plates ◽  
Shear Stresses ◽  
Mean Velocity ◽  
Contour Maps ◽  
Velocity Decay ◽  
Spreading Rates

SummaryJets issuing from rectangular slots cut in thin plates exhibit some unusual features, including unequal spreading rates in the spanwise and transverse directions, the appearance of velocity peaks near the “ends” of the jet and changing rates of centreline velocity decay in the downstream direction. This study examines the effects of aspect ratio on such flows. The flow field has been investigated using both total head tubes and hot wire anemometry. The results are presented in the form of three-dimensional plots of total pressure and contour maps of constant velocity, streamwise turbulence intensity and the Reynolds shear stresses. The decay of mean velocity and stream-wise turbulence intensity along the centreline are presented. The rates of spanwise spreading and the location of the velocity peaks at various downstream stations are discussed. If the aspect ratio is small enough, spanwise peaks in the mean velocity distribution are suppressed.

An Explicit Non-Real Time Data Reduction Method of Triple Sensors Hot-Wire Anemometer in Three-Dimensional Flow

1988 ◽  
Vol 110 (2) ◽  
pp. 110-119 ◽  
Author(s):  
Y. T. Chew ◽  
R. L. Simpson
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Computation Time ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Time Data ◽  
Three Dimensional Flow ◽  
Mean Velocity ◽  
Dimensional Flow ◽  
The Mean

An explicit non-real time method of reducing triple sensor hot-wire anenometer data to obtain the three mean velocity components and six Reynolds stresses, as well as their turbulence spectra in three-dimensional flow is proposed. Equations which relate explicitly the mean velocity components and Reynolds stresses in laboratory coordinates to the mean and mean square sensors output voltages in three stages are derived. The method was verified satisfactorily by comparison with single sensor hot-wire anemometer measurements in a zero pressure gradient incompressible turbulent boundary layer flow. It is simple and requires much lesser computation time when compared to other implicit non-real time method.

An Experimental Study of Three-Dimensional Turbulent Boundary Layer and Turbulence Characteristics Inside a Turbomachinery Rotor Passage

1978 ◽  
Vol 100 (4) ◽  
pp. 676-687 ◽  
Author(s):  
A. K. Anand ◽  
B. Lakshminarayana
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Turbulence Intensity ◽  
Three Dimensional ◽  
Stream Line ◽  
Shear Stresses ◽  
Axial Pressure ◽  
Mean Velocity ◽  
Large Defect ◽  
Axial Pressure Gradient

Three-dimensional boundary layer and turbulence measurements of flow inside a rotating helical channel of a turbomachinery rotor are described. The rotor is a four-bladed axial flow inducer operated at large axial pressure gradient. The mean velocity profiles, turbulence intensities and shear stresses, and limiting stream-line angles are measured at various radial and chordwise locations, using rotating triaxial hot-wire and conventional probes. The radial flows in the rotor channel are found to be higher compared to those at zero or small axial pressure gradient. The radial component of turbulence intensity is found to be higher than the streamwise component due to the effect of rotation. Flow near the annulus wall is found to be highly complex due to the interaction of the blade boundary layers and the annulus wall resulting in an appreciable radial inward flow, and a large defect in the mainstream velocity. Increased level of turbulence intensity and shear stresses near the midpassage are also observed near this radial location.

On the mean motion induced by internal gravity waves

1969 ◽  
Vol 36 (4) ◽  
pp. 785-803 ◽  
Author(s):  
Francis P. Bretherton
Keyword(s):  
Gravity Waves ◽  
Wave Energy ◽  
Wave Train ◽  
Three Dimensional ◽  
Internal Gravity Waves ◽  
Wave Number ◽  
Mean Flow ◽  
Mean Velocity ◽  
Mean Motion ◽  
The Mean

A train of internal gravity waves in a stratified liquid exerts a stress on the liquid and induces changes in the mean motion of second order in the wave amplitude. In those circumstances in which the concept of a slowly varying quasi-sinusoidal wave train is consistent, the mean velocity is almost horizontal and is determined to a first approximation irrespective of the vertical forces exerted by the waves. The sum of the mean flow kinetic energy and the wave energy is then conserved. The circulation around a horizontal circuit moving with the mean velocity is increased in the presence of waves according to a simple formula. The flow pattern is obtained around two- and three-dimensional wave packets propagating into a liquid at rest and the results are generalized for any basic state of motion in which the internal Froude number is small. Momentum can be associated with a wave packet equal to the horizontal wave-number times the wave energy divided by the intrinsic frequency.

Effect of Freestream Turbulence and Flow Recovery in the Wake of a Flat Plate

2002 ◽  
Author(s):  
F. N. Krampa-Morlu ◽  
R. Balachandar
Keyword(s):  
Flat Plate ◽  
Turbulence Intensity ◽  
Flow Direction ◽  
Wake Region ◽  
Freestream Turbulence ◽  
Near Wake ◽  
Mean Velocity ◽  
Channel Boundary ◽  
The Mean ◽  
Velocity Turbulence

The study of the recovery of an open channel boundary flow in the presence of increased freestream turbulence (FST) generated in the wake region of a surface mounted flat plate is presented. Detailed LDA velocity measurements were obtained upstream and downstream of the flat plate, which is 3 mm in thickness and has a thickness-to-chord ratio of 0.12. The chord is placed parallel to the flow direction. The characteristics of the mean velocity, turbulence intensity, and the velocity skewness and flatness factors were investigated. The skin friction was increased while the strength of the boundary layer wake parameter decreased in the wake region. The turbulence intensity profiles in the wake region increasingly deviated significantly from the upstream profile. Generally, the increased FST noticed in the near-wake region was observed to decay with downstream distance. As a result, the mean velocity and turbulence intensity profiles showed a general sense of recovery towards the state of the approaching flow.

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