Pressure and Velocity Measurements

2013 ◽  
Author(s):  
Richard S. Figliola ◽  
Donald E. Beasley
Keyword(s):  
Velocity Measurements ◽  
Pressure And Velocity Measurements

Self-sustained oscillation of a jet impinging upon a Helmholtz resonator

1987 ◽  
Vol 179 ◽  
pp. 77-103 ◽  
Author(s):  
W. M. Jungowski ◽  
G. Grabitz
Keyword(s):  
Helmholtz Resonator ◽  
Sustained Oscillation ◽  
Flow Oscillation ◽  
Velocity Measurements ◽  
Fluctuating Pressure ◽  
Air Jet ◽  
Oscillation Mechanism ◽  
Large Pressure ◽  
Detached Shock Wave ◽  
Pressure And Velocity Measurements

A planar, sonic, underexpanded air jet induced strong and self-sustained flow oscillation. The jet was bounded by two parallel walls extending between the nozzle and the Helmholtz resonator opposite. This oscillation was characterized by large pressure amplitudes in the resonator and periodic displacement of a detached shock wave. The observed phenomena were in some measure similar to those occurring with Hartmann-Sprenger tubes. Based on the experimental results, including Mach-Zehnder interferograms and fluctuating pressure and velocity measurements, the properties of the oscillation have been described and a model for theoretical analysis has been established. Experimental and numerical investigations have made possible a description of the oscillation mechanism, which is of the relaxation type.

Study of the Steady-State Flow Pattern in a Multipulse Converter by LDA

1988 ◽  
Vol 110 (3) ◽  
pp. 515-522 ◽  
Author(s):  
P. Flamang ◽  
R. Sierens
Keyword(s):  
Steady State ◽  
Cross Sections ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Velocity Measurements ◽  
Pulse Converter ◽  
Flow Situation ◽  
Flow Configurations ◽  
Pressure And Velocity Measurements ◽  
Mixing Losses

This paper describes pressure and velocity measurements on a multipulse converter under steady-state conditions. Pressure loss coefficients were measured on this four-entry pulse converter system for a large number of flow configurations. Three-dimensional velocity measurements were done (with Laser-Doppler anemometry) for several flow configurations and at different cross sections in the converter. The normal flow situation (incoming flow at the four entries) and back flow situations were examined. For each cross section the axial velocity profiles, the secondary flow patterns, and the turbulent velocities are presented. From the pressure measurements mixing losses are derived. These are compared with the results of a one-dimensional calculation, which is based on the impulse law for incompressible flow. Taking into account the velocity measurements, this simplified model gives a remarkable agreement with the measured mixing losses.

Augmented Heat Transfer in a Recovery Passage Downstream From a Grooved Section: An Example of Uncoupled Heat/Momentum Transport

1995 ◽  
Vol 117 (2) ◽  
pp. 303-308 ◽  
Author(s):  
M. Greiner ◽  
R.-F. Chen ◽  
R. A. Wirtz
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Pumping Power ◽  
Power Performance ◽  
Velocity Measurements ◽  
Cross Sectional ◽  
Number Range ◽  
Transverse Grooves ◽  
Pressure And Velocity Measurements ◽  
The Heat Transfer Coefficient

Earlier experiments have shown that cutting transverse grooves into one surface of a rectangular cross-sectional passage stimulates flow instabilities that greatly enhance heat transfer/pumping power performance of air flows in the Reynolds number range 1000 < Re < 5000. In the current work, heat transfer, pressure, and velocity measurements in a flat passage downstream from a grooved region are used to study how the flow recovers once it is disturbed. The time-averaged and unsteady velocity profiles, as well as the heat transfer coefficient, are dramatically affected for up to 20 hydraulic diameters past the end of the grooved section. The recovery lengths for shear stress and pressure gradient are significantly shorter and decrease rapidly for Reynolds numbers greater than Re = 3000. As a result, a 5.4-hydraulic-diameter-long recovery region requires 44 percent less pumping power for a given heat transfer level than if grooving continued.

Sign in / Sign up

Export Citation Format

Share Document