TITLE

Low Air Velocity Measurement Characteristics' Variation Due to Flow Regime

AUTHOR(S)
Pedišius, A.; Janušas, V.; Bertašienė, A.
PUB. DATE
June 2008
SOURCE
Proceedings of World Academy of Science: Engineering & Technolog;Jun2008, Vol. 42, p203
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The paper depicts air velocity values, reproduced by laser Doppler anemometer (LDA) and ultrasonic anemometer (UA), relations with calculated ones from flow rate measurements using the gas meter which calibration uncertainty is ± (0.15 - 0.30) %. Investigation had been performed in channel installed in aerodynamical facility used as a part of national standard of air velocity. Relations defined in a research let us confirm the LDA and UA for air velocity reproduction to be the most advantageous measures. The results affirm ultrasonic anemometer to be reliable and favourable instrument for measurement of mean velocity or control of velocity stability in the velocity range of 0.05 m/s - 10 (15) m/s when the LDA used. The main aim of this research is to investigate low velocity regularities, starting from 0.05 m/s, including region of turbulent, laminar and transitional air flows. Theoretical and experimental results and brief analysis of it are given in the paper. Maximum and mean velocity relations for transitional air flow having unique distribution are represented. Transitional flow having distinctive and different from laminar and turbulent flow characteristics experimentally have not yet been analysed.
ACCESSION #
33132498

 

Related Articles

  • Laser measures up, even in steam. Braham, James // Machine Design;08/07/97, Vol. 69 Issue 15, p35 

    Examines the first successful use of a laser doppler anemometer (LDA), which measures precise velocity, by the Westinghouse Science and Technology Center (STC). Information on the scientific development of a protective cooling system for LDA; Information on the safety feature of the LDA;...

  • Laser Doppler measurement of turbulence parameters in a two-dimensional plane wall jet. Schneider, M. E.; Goldstein, R. J. // Physics of Fluids;Sep94, Vol. 6 Issue 9, p3116 

    A computer-controlled data acquisition system has been designed and constructed to automate measurement of turbulent velocity correlations in a two-dimensional turbulent wall jet. Measurements are made with a single component laser Doppler velocimeter system in a flow of air on a flat plate with...

  • Laser Doppler anemometry measurements in an axisymmetric turbulent jet. Kassab, Sadek Z.; Bakry, Ayman E.; Warda, Hassan A. // Review of Scientific Instruments;May96, Vol. 67 Issue 5, p1842 

    Investigates some aspects related to the characteristics of turbulent jet flow using laser Doppler anemometry (LDA) as a measuring technique. Air jet facility and measurement scheme; Comparison between unweighted and weighted mean fluctuating velocities along the jet center line; Repeatability...

  • Demonstration of a laser vorticity probe in turbulent boundary layers. Su, W-J.; Stepaniuk, V.; Ötügen, M. V. // Review of Scientific Instruments;Sep2007, Vol. 78 Issue 9, p095106 

    A laser-based probe for the nonintrusive measurement of velocity gradient and vorticity was demonstrated in turbulent boundary layers. Unlike most other optical methods, the current technique provides an estimate of the velocity gradient, without having to first measure velocity at multiple...

  • Demonstration of a laser vorticity probe in turbulent boundary layers. Su, W-J.; Stepaniuk, V.; Ötügen, M. V. // Review of Scientific Instruments;Sep2007, Vol. 78 Issue 9, p095106 

    A laser-based probe for the nonintrusive measurement of velocity gradient and vorticity was demonstrated in turbulent boundary layers. Unlike most other optical methods, the current technique provides an estimate of the velocity gradient, without having to first measure velocity at multiple...

  • Simulated WSR-88D Velocity and Reflectivity Signatures of Numerically Modeled Tornadoes. Wood, Vincent T.; Brown, Rodger A.; Dowell, David C. // Journal of Atmospheric & Oceanic Technology;May2009, Vol. 26 Issue 5, p876 

    Low-altitude radar reflectivity measurements of tornadoes sometimes reveal a donut-shaped signature (low-reflectivity eye surrounded by a high-reflectivity annulus) and at other times reveal a high-reflectivity knob associated with the tornado. The differences appear to be due to such factors as...

  • Experimental Methods in Ventilation. Sandberg, M.; Lundström, H.; Nilsson, H. O.; Stymne, H. // Advances in Building Energy Research;2008, Vol. 2, p159 

    This chapter describes different experimental methods related to the function of ventilation. Methods of thermal comfort are also treated. A classical, comprehensive review paper on this subject is found in Hitchin and Wilson (1961). Much information provided by this paper is still valid,...

  • Laser anemometer measurements of Reynolds stress in a turbulent channel flow with drag reducing polymer additives. Willmarth, W. W.; Wei, T.; Lee, C. O. // Physics of Fluids (00319171);Apr87, Vol. 30 Issue 4, p933 

    Turbulence measurements with a high resolution laser Doppler anemometer in a channel flow with injection of a concentrated polyethylene oxide solution are reported. With polymer injection sufficient to yield a well mixed concentration of 10 ppm the total drag is reduced by 38%, but the sum of...

  • Relative velocity fluctuations in turbulent flows at moderate Reynolds numbers. I. Experimental. Tong, P.; Goldburg, W. I. // Physics of Fluids (00319171);Oct88, Vol. 31 Issue 10, p2841 

    Turbulent pipe flow and grid flow have been explored by the scattering of light from small particles suspended in a fluid. Laser Doppler velocimetry and visual observation were used to characterize the gross features of the flows. However, novel information came from the homodyne correlation...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics