Velocity and Static-Pressure Distributions in Swirling Air Jets Issuing From Annular and Divergent Nozzles

1964 ◽  
Vol 86 (4) ◽  
pp. 788-796 ◽  
Author(s):  
N. A. Chigier ◽  
J. M. Bee´r
Keyword(s):  
Static Pressure ◽  
Reverse Flow ◽  
Ring Vortex ◽  
Pressure Gradients ◽  
Mean Velocity ◽  
Air Jets ◽  
Pressure Distributions ◽  
Angular Momenta ◽  
Set Up ◽  
Made In

Mean-velocity and static-pressure measurements have been made in a series of swirling air jets issuing from annular and divergent nozzles into stagnant-air surroundings. Swirl was generated by introducing varying proportions of air through tangential ports while the remainder of the air was introduced axially. A region of subatmospheric pressure is set up in the central region of the jets and as soon as the pressure gradients on the axis exceed a certain critical value, reverse flow is set up with an associated internal ring vortex. With increasing degrees of swirl, the angle of spread of the jets is increased and, correspondingly, the decay of the maximum values of axial, tangential, and radial components of velocity along the lengths of the jets is faster. The integrated axial fluxes of linear and angular momenta were shown to be conserved along the length of the jets.

The Flow Region Near the Nozzle in Double Concentric Jets

1964 ◽  
Vol 86 (4) ◽  
pp. 797-804 ◽  
Author(s):  
N. A. Chigier ◽  
J. M. Bee´r
Keyword(s):  
Static Pressure ◽  
Flow Region ◽  
Mean Velocity ◽  
Pressure Distributions ◽  
Air Jet ◽  
The Mean ◽  
Annular Jets ◽  
Made In

The type of double concentric jets considered in this paper consists of a central round air jet surrounded by an annular air jet issuing into stagnant air surroundings. Detailed measurements of the mean velocity and static-pressure distributions have been made in the region close to the exit of the nozzles and the effect of varying the ratio of the velocities in the central and annular jets has been examined.

Mean velocity and static pressure distributions of a circular jet

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 196-197
Author(s):  
M. T. Islam ◽  
M. A. T. Ali
Keyword(s):  
Static Pressure ◽  
Mean Velocity ◽  
Pressure Distributions

Static pressure distribution in the free turbulent jet

1957 ◽  
Vol 3 (1) ◽  
pp. 1-16 ◽  
Author(s):  
David R. Miller ◽  
Edward W. Comings
Keyword(s):  
Static Pressure ◽  
Longitudinal Velocity ◽  
Fluid Motion ◽  
Mean Velocity ◽  
Free Jet ◽  
Static Pressure Distribution ◽  
Two Dimensional Flow ◽  
The Common ◽  
Jet Theory ◽  
Made In

Measurements of mean velocity, turbulent stress and static pressure were made in the mixing region of a jet of air issuing from a slot nozzle into still air. The velocity was low and the two-dimensional flow was effectively incompressible. The results are examined in terms of the unsimplified equations of fluid motion, and comparisons are drawn with the common assumptions and simplifications of free jet theory. Appreciable deviations from isobaric conditions exist and the deviations are closely related to the local turbulent stresses. Negative static pressures were encountered everywhere in the mixing field except in the potential wedge region immediately adjacent to the nozzle. Lateral profiles of mean longitudinal velocity conformed closely to an error curve at all stations further than 7 slot widths from the nozzle mouth. An asymptotic approach to complete self-preservation of the flow was observed.

Flow Characteristics of Swirling Coaxial Jets From Divergent Nozzles

1987 ◽  
Vol 109 (3) ◽  
pp. 275-282 ◽  
Author(s):  
T. Mahmud ◽  
J. S. Truelove ◽  
T. F. Wall
Keyword(s):  
Bituminous Coal ◽  
Static Pressure ◽  
Reverse Flow ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
Flow Zone ◽  
Mean Velocity ◽  
Coaxial Jets ◽  
Mass Flowrate

The aerodynamic characteristics of free, swirling, coaxial jets issuing from an air model of a typical burner for pulverized bituminous coal have been studied. Detailed measurements of mean velocity and static pressure have been obtained in the region near the nozzle exit. The boundary of the reverse-flow zone has been mapped and the recirculated-mass flowrate measured in order to quantify the effects of velocity ratio and swirl in the primary and secondary jets. The influence of burner geometry (divergent-nozzle length and centre-line blockage) has also been studied. The type of flow pattern is found to depend upon the level of swirl in the primary and secondary jets. The recirculated-mass flowrate is predominantly influenced by secondary swirl. The measurements have been compared with predictions obtained by numerical solution of the governing conservation equations in orthogonal curvilinear co-ordinates. The general features of the flows are adequately predicted although discrepancies in detail seem to indicate deficiencies in the turbulence model.

Arbitrary Mean Flow in Adverse Pressure Gradients

1971 ◽  
Vol 93 (4) ◽  
pp. 495-499 ◽  
Author(s):  
G. M. Bragg ◽  
J. K. Suk
Keyword(s):  
Adverse Pressure Gradient ◽  
Maximum Error ◽  
Velocity Profiles ◽  
Turbulent Wake ◽  
Pressure Gradients ◽  
Local Velocity ◽  
Calculation Methods ◽  
Mean Flow ◽  
Mean Velocity ◽  
Made In

Measurements of mean velocity profiles were made in the turbulent wake behind a single cylinder as well as a row of parallel, arbitrarily spaced and arbitrarily sized cylinders with an adverse pressure gradient. Two currently available calculation methods, based on a simple superposition of momentum, and a step-by-step finite difference procedure, were applied to the prediction of mean velocity profiles in the wake. The agreement between the predicted and the observed results is good in most cases with maximum error less than 18 percent of significant velocity defects or 3 percent of local velocity.

Mean Velocity and Static Pressure Distributions of a Circular Jet

AIAA Journal ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 196-197 ◽  
Author(s):  
M. T. Islam ◽  
M. A. T. Ali
Keyword(s):  
Static Pressure ◽  
Mean Velocity ◽  
Pressure Distributions

Wakes in Axial Compressors

1959 ◽  
Vol 63 (583) ◽  
pp. 415-416 ◽  
Author(s):  
H. Pearson ◽  
A. B. McKenzie
Keyword(s):  
Static Pressure ◽  
Early Stage ◽  
Axial Compressor ◽  
Pressure Gradients ◽  
Blade Vibration ◽  
Axial Compressors ◽  
Pressure Distributions ◽  
The People ◽  
Total Head ◽  
Flow Test

The tendency in the past has been to assume that when wakes or non-uniform total head profiles are fed into an axial compressor then substantially constant static pressure prevails at the entry, the variations in total head appearing as variations in velocity. This variation in velocity causes variation in incidence on the early stage blade rows and thus can give rise to excitation of blade vibration. This assumption is implicit, for instance, in References 1 and 2, but we think has been a common assumption by most of the people working in this field.Where the compressor is fed by a duct of substantially parallel walls for a reasonable length ahead, such an assumption appeared justifiable. Such a duct when given an air flow test with its outlet discharging, for instance, to atmosphere instead of to the compressor, then the distribution assumed would normally be obtained and in fact many surveys of such ducts have been represented in this fashion. The object of this note is to show that, in fact, this distribution will not normally occur when the compressor is present and we may normally expect much more nearly a constant velocity into the compressor with attendant static pressure distributions to match with the total head variations ahead of the intake, with of course, the attendant curved flow to support the static pressure gradients.

Some Aspects of Three-Dimensional Cavity Flow

1957 ◽  
Vol 61 (557) ◽  
pp. 345-352
Author(s):  
A. J. Taylor-Russell
Keyword(s):  
Static Pressure ◽  
Three Dimensional ◽  
Cavity Flow ◽  
Wake Flow ◽  
Flat Plates ◽  
Mean Velocity ◽  
Wake Flows ◽  
Low Aspect Ratio ◽  
Recirculatory Flow ◽  
Made In

SummarySome experiments concerned with the wake flows of a number of flat plates of low aspect ratio (Fail, Owen and Eyre) have suggested that for large angles of inclination to the undisturbed stream the wake includes a region of recirculation. The present observations include a detailed study of this region, with particular reference to the wake produced by an equilateral triangular plate, and an attempt is made to explain why the recirculatory flow is found only at angles of incidence greater than 35°. The data includes some wind tunnel measurements of force coefficients, static pressure and mean velocity, and observations of the wake flow made in a smoke tunnel and in a water tunnel.

The Attachment of a Ventilated Plane Jet to an Inclined Plane Wall

1978 ◽  
Vol 29 (2) ◽  
pp. 60-74 ◽  
Author(s):  
G.F. Marsters
Keyword(s):  
Static Pressure ◽  
Plane Wall ◽  
Pressure Gradients ◽  
Inclined Plane ◽  
Wall Angle ◽  
Pressure Distributions ◽  
Jet Nozzle ◽  
The Mean ◽  
Plane Jet ◽  
Fair Degree

SummaryThe behaviour of a plane jet issuing in the neighbourhood of a plane wall has been studied experimentally. Such arrangements may find application in jet augmented flaps for STOL aircraft development. The essential features of this configuration are the gap between the wall and the jet nozzle, permitting entrainment of secondary flow, and the inclination of the plane wall with respect to the nozzle axis.Measurements of velocity profiles, wall static pressure distributions and turbulence intensities reveal the presence of extensive regions of low pressure over the wall, strong pressure gradients resulting in the highly curved flow, a fair degree of self-preservation of the mean velocities, but no particularly unusual features observed in the turbulence quantities. The size of the gap, the wall angle and the wall length all influence the reattachment location, and limits of gap, angle and length for which reattachment occurs are shown. The sub-ambient static pressure regions give rise to significant forces on the wall; these forces are primarily due to the entrainment feature.

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