scholarly journals Spanwise structure of wall pressure on a cylinder in axial flow

1999 ◽  
Vol 11 (1) ◽  
pp. 151-161 ◽  
Author(s):  
Arun L. W. Bokde ◽  
Richard M. Lueptow ◽  
Bruce Abraham
Keyword(s):  
Axial Flow ◽  
Wall Pressure

The flow of swirling water through a convergentdivergent nozzle

1957 ◽  
Vol 3 (3) ◽  
pp. 261-274 ◽  
Author(s):  
A. M. Binnie ◽  
G. A. Hookings ◽  
M. Y. M. Kamel
Keyword(s):  
Axial Flow ◽  
Low Pressure ◽  
Wall Pressure ◽  
Core Diameter ◽  
Convergent Nozzle ◽  
Marked Influence ◽  
The Core ◽  
Air Core ◽  
Pressure Tests

Experiments with Perspex nozzles, which were arranged to discharge vertically downwards and in which the convergent part was followed by a short divergency, showed that at low swirls the flow was unstable. When the swirl was sufficiently large for an air core to be established, its effective magnitude was estimated from measurements, at the throat, of the core diameter and of the wall pressure. The former were in closer accord with inviscid theory than the latter. The results are presented in terms of dimensionless discharge and swirl coefficients. Measurements of core diameter and wall pressure were also made throughout one of the nozzles and compared with the theory. Reversed axial flow in the upper part of the nozzles was easily produced, and the limits of its appearance were determined. Low pressure tests with the reservoir top alternately submerged and uncovered revealed that the top had a marked influence on the nature of the flow in the nozzle; and measurements of the tangential and axial velocities in the upper part of the nozzle proved the inviscid theory to be seriously in error at high swirls. For purposes of comparison, similar experiments were performed on a convergent nozzle.

Measurement of wall pressure fluctuations for noise prediction in axial flow fans

2008 ◽  
Vol 123 (5) ◽  
pp. 3688-3688
Author(s):  
Jérémy Hurault ◽  
Smaine Kouidri ◽  
Farid Bakir ◽  
Robert Rey
Keyword(s):  
Pressure Fluctuations ◽  
Axial Flow ◽  
Wall Pressure ◽  
Noise Prediction ◽  
Wall Pressure Fluctuations

Exit Flow Behavior of Axial Fan Flows With/Without Impingement

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
D. Sui ◽  
S. S. Wang ◽  
J. R. Mao ◽  
T. Kim ◽  
T. J. Lu
Keyword(s):  
Flow Behavior ◽  
Axial Flow ◽  
Electronics Cooling ◽  
Wall Pressure ◽  
Axial Fan ◽  
Stagnation Region ◽  
Flow Recirculation ◽  
Plate Spacing ◽  
Flow Interaction ◽  
Plate Center

The exit flow patterns of an axial flow fan widely used in electronics cooling are experimentally characterized both in free exit and in the presence of a flat impingement plate. The axial fan is rotated with 12.0 V input from a dc power supply, leading to a nominal Reynolds number of Re=9.0×103 based on fan diameter. One shear layer each is found to form between the exit flow from the axial fan and the surrounding fluid at rest, and between the exit flow and the flow along the fan axis. In addition to creating a highest wall pressure region (the primary stagnation region), the presence of the flat plate induces a flow recirculation zone (the secondary stagnation region) at the plate center. When the fan exit-to-plate spacing normalized by fan diameter (H/D) equals to about 0.6, the wall pressure is minimized in the secondary stagnation region due to the maximized “recirculation” as a result of intensified flow interaction. Within the range considered (0.2≤H/D≤2.0) and with the case of H/D∼0.6 serving as a reference, the flow interaction tends to be suppressed by the proximity of the plate at H/D=0.2 and weakened due to the momentum dissipation at H/D∼2.0.

Stall inception phenomena in a single-stage axial-flow pump

2003 ◽  
Vol 217 (4) ◽  
pp. 471-479 ◽  
Author(s):  
I Goltz ◽  
G Kosyna ◽  
U Stark ◽  
H Saathoff ◽  
S Bross
Keyword(s):  
Axial Flow ◽  
Wall Pressure ◽  
Operating Conditions ◽  
Single Stage ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Stall Inception ◽  
Oil Flow ◽  
Axial Flow Pump ◽  
Flow Pump

The paper describes an experimental investigation on stall inception phenomena in a single-stage axial-flow pump, utilizing an oil flow technique and two different photo techniques. Moreover, the unsteady casing wall pressure was measured. Representative results are shown and discussed: the pump characteristic for two different NPSH values, selected oil flow pictures of the casing wall and the rotor blades, the wall pressure distribution at design, selected pictures of the cavitating core of the tip clearance vortex at stable and unstable operating conditions and the visualization of a cross-passage vortex as a deep stall phenomenon. These results allow a number of key features of the stall inception process to be identified and to be followed along the unstable part of the pump characteristic.

scholarly journals Numerical Prediction of Wall Pressure Fluctuations in a Turbulent Boundary Layer on a Cylinder in Axial Flow

2019 ◽  
Vol 9 (1S4) ◽  
pp. 625-628
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Fluctuations ◽  
Axial Flow ◽  
Wall Pressure ◽  
Flow Noise ◽  
Eddy Simulation ◽  
Wall Pressure Fluctuations ◽  
Large Eddy ◽  
Long Cylinder

Flow noise originating in the turbulent boundary layer (TBL) often severely limits the performance of towed sonar cylinder and therefore it is necessary to predict this noise for the design of efficient towed cylinder. This paper presents large eddy simulation methodology to establish the TBL properties and wall pressure fluctuations on a 3 m long cylinder with length to diameter ratio of 315 in the operating speed of 11.4 m/s in air. The computed flow induced sound is compared with experimental measurement available in the literature successfully. The effectiveness of scaling the flow noise spectra with diameter and tow speed is discussed and non-dimensional wall pressure spectra presented with respect to non-dimensional frequency. The overall sound pressure levels are also compared with experimental data that show good accuracy achieved by the proposed numerical methodology.

Sign in / Sign up

Export Citation Format

Share Document