Axisymmetrical Turbulent Swirling Natural-Convection Plume: Part 2—Experimental Investigation

1966 ◽  
Vol 33 (3) ◽  
pp. 656-661 ◽  
Author(s):  
Shao-Lin Lee
Keyword(s):  
Experimental Investigation ◽  
Natural Convection ◽  
Velocity Fields ◽  
Hot Wire ◽  
Ambient Fluid ◽  
Wire Probe ◽  
Characteristic Radius ◽  
Burner Flame ◽  
Theoretical Predictions ◽  
Temperature And Velocity Fields

An experimental investigation is made of the behavior of an axisymmetrical turbulent swirling natural-convection plume in an otherwise motionless ambient fluid. The swirling plume is issued from the exit of a swirling-plume generator which couples the hot gases from a Bunsen burner flame and the swirling mass of air from a ring of distributed tangential jets. Temperature and velocity fields of the swirling plume are measured by the use of a temperature-calibrated, V-shaped hot-wire probe. Measured results of the vertical and swirling velocities, the temperature, and the characteristic radius of the swirling plume are found to agree closely with the theoretical predictions of Part 1.

Calibration of Constant-Temperature Hot-Wire Anemometers at Low Velocities in Water with Variable Fluid Temperature

1972 ◽  
Vol 94 (1) ◽  
pp. 17-22 ◽  
Author(s):  
K. Hollasch ◽  
B. Gebhart
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Constant Temperature ◽  
Fluid Temperature ◽  
Hot Wire ◽  
Temperature Variations ◽  
Wire Probe ◽  
Temperature Mode

Calibration of hot-wire probes operated in a constant-temperature mode in water at low velocities is discussed. Operation under circumstances where natural convection effects are important is considered. A method of calibrating a constant-temperature hot-wire probe for variations in fluid temperature is presented. The method consists of varying wire overheat during calibration at a constant fluid temperature. A relation is derived analytically relating anemometer output with a variable overheat resistance to anemometer output with fluid temperature variations. An experimental study to verify the analysis is presented.

Manipulation of the Flow Around a Circular Cylinder by Utilizing the Flow Receptivity

2007 ◽  
Author(s):  
Yasuaki Kozato ◽  
Satoshi Kikuchi ◽  
Shigeki Imao
Keyword(s):  
Circular Cylinder ◽  
Shear Layer ◽  
Vortex Shedding ◽  
Velocity Fields ◽  
Shear Layer Instability ◽  
Hot Wire ◽  
Acoustic Disturbance ◽  
Wire Probe ◽  
Separated Shear Layer ◽  
Karman Vortex

An attempt to control the flow around a circular cylinder by utilizing the receptivity to the external acoustic disturbance was carried out and its mechanism was also studied. The velocity fields around the cylinder vicinity are carefully investigated with an X-type hot-wire probe. When the disturbance of a higher frequency related to the separated shear layer instability is added, the development of turbulence and the spreading of the shear layer are restrained. And, the amplification of the fluctuating velocity component of the Karman vortex shedding is delayed and its degree is reduced. Furthermore, the process of the gradual scale modification of the shear layer instability that appears prior to the transition of the flow is suppressed.

The second-law analysis of convective pattern change in a rectangular cavity

1999 ◽  
Vol 392 ◽  
pp. 361-377 ◽  
Author(s):  
UICHIRO NARUSAWA
Keyword(s):  
Natural Convection ◽  
Entropy Generation ◽  
Critical Rayleigh Number ◽  
Velocity Fields ◽  
Rectangular Cavity ◽  
Second Law ◽  
Free Boundaries ◽  
Pattern Change ◽  
Convective Pattern ◽  
Temperature And Velocity Fields

Natural convection in a rectangular cavity is examined, utilizing the second law of thermodynamics. Through an application of the second law the rate of entropy generation associated with the convective pattern changes is evaluated for the onset of natural convection in a cavity with free boundaries, for which an exact solution is sought, as well as with rigid boundaries which is studied numerically. Entropy to be generated from the perturbed temperature and velocity fields is shown to depend on AR (aspect ratio of the cavity), Rac (the critical Rayleigh number) and a non-dimensional parameter, Ω, which is related to the ratio of entropy generation by viscous friction to that by thermal transport. The convective pattern change is related to a change in the spatial distributions of the rate of entropy generation due to heat transfer and due to dissipation, demonstrating that an application of the second law helps examine convective pattern changes quantitatively by dealing with temperature and velocity fields in a unified manner.

scholarly journals Experimental Investigation on Rotating Stall in a Centrifugal Blower With Two and Four Stages and Vaneless Diffusers

1996 ◽  
Author(s):  
Gianmario L. Arnulfi ◽  
Diego Micheli ◽  
Piero Pinamonti
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Rotating Stall ◽  
Test Plant ◽  
Hot Wire ◽  
Centrifugal Blower ◽  
Stall Inception ◽  
Wire Probe ◽  
Instantaneous Flow Field ◽  
Vaneless Diffusers

The paper presents the results of an experimental investigation on a multistage centrifugal blower, during rotating stall. The test plant allows to change the turbomachine characteristics; in this research the blower has been tested in two different configurations: two-stage and four-stage, with vaneless diffusers. The unsteady flow field inside the blower has been measured by means of hot-wire anemometers. Three single hot-wire probes have been utilised to measure the development of the rotating stall, while a crossed hot-wire probe has been utilised to obtain the instantaneous flow field behind the impellers. The measurements have been done at different flow rate values, including stall inception.

An Experimental Investigation of Auditors' Liability: Implications for Social Welfare and Exploration of Deviations from Theoretical Predictions

2000 ◽  
Vol 75 (4) ◽  
pp. 429-451 ◽  
Author(s):  
Ronald R. King ◽  
Rachel Schwartz
Keyword(s):  
Experimental Investigation ◽  
Social Welfare ◽  
Strict Liability ◽  
Liability Rule ◽  
Optimal Response ◽  
Legal Regimes ◽  
Theoretical Predictions ◽  
Best Responses

This paper reports the results of an experiment designed to investigate how legal regimes affect social welfare. We investigate four legal regimes, each consisting of a liability rule (strict or negligence) and a damage measure (out-of-pocket or independent-of-investment). The results of the experiment are for the most part consistent with the qualitative predictions of Schwartz's (1997) model; however, subjects' actual choices deviate from the point predictions of the model. We explore whether these deviations arise because: (1) subjects form faulty anticipations of their counterparts' actions and/or (2) subjects do not choose the optimal responses given their anticipations. We find that subjects behave differently under the four regimes in terms of anticipation errors and departures from best responses. For example, subjects playing the role of auditors anticipate investments most accurately under the regime with strict liability combined with out-of-pocket damages, but are least likely to choose the optimal response given their anticipations. This finding implies that noneconomic factors likely play a role in determining subjects' choices.

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