scholarly journals Non-mechanical scanning laser Doppler velocimetry with sensitivity to direction of transverse velocity component using optical serrodyne frequency shifting

2014 ◽  
Vol 319 ◽  
pp. 80-84 ◽  
Author(s):  
Koichi Maru ◽  
Kento Watanabe
Keyword(s):  
Velocity Component ◽  
Laser Doppler Velocimetry ◽  
Transverse Velocity ◽  
Laser Doppler ◽  
Scanning Laser ◽  
Doppler Velocimetry ◽  
Transverse Velocity Component ◽  
Mechanical Scanning ◽  
Frequency Shifting

Velocity Fluctuations at the Walls of a Packed Bed of Spheres for Medium Re-Numbers

1987 ◽  
Vol 109 (3) ◽  
pp. 242-247 ◽  
Author(s):  
R. H. Bahnen ◽  
C. G. Stojanoff
Keyword(s):  
Velocity Component ◽  
Laser Doppler Velocimetry ◽  
Convex Surface ◽  
Packed Bed ◽  
Experimental Results ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Cylindrical Container ◽  
Velocity Fluctuations ◽  
Different Diameters

A packed bed which is uniformly filled with equally large spheres is subjected to transpiration flow. The velocity component perpendicular to its surface was measured by means of Laser-Doppler-Velocimetry. Special attention is paid to the velocity fluctuations occurring at the wall of the cylindrical container and at the convex surface of rods of different diameters inserted in the bed center. The Re-numbers were between 800 and 1500. The experimental results are compared with results obtained from the literature.

scholarly journals Laser doppler velocimetry and confined flows

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 825-836
Author(s):  
Jelena Ilic ◽  
Slavica Ristic ◽  
Milesa Sreckovic
Keyword(s):  
Velocity Component ◽  
Laser Doppler Velocimetry ◽  
Focal Length ◽  
Cylindrical Tube ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Focal Length Lens ◽  
Cylindrical Tubes ◽  
Set Up ◽  
Confined Flows

Finding the mode, in which two component laser Doppler velocimetry can be applied to flows confined in cylindrical tubes or vessels, was the aim of this study. We have identified principle issues that influence the propagation of laser beams in laser Doppler velocimetry system, applied to flow confined in cylindrical tube. Among them, the most important are influences of fluid and wall refractive indices, wall thickness and internal radius ratio and beam intersection angle. In analysis of the degrees of these influences, we have applied mathematical model, based on geometrical optics. The separation of measurement volumes, that measure different velocity components, has been recognized as the main drawback. To overcome this, we propose a lens with dual focal length ? primary focal length for the measurement of one velocity component and secondary focal length for the measurement of the other velocity component. We present here the procedure for calculating the optimal value of secondary focal length, depending on experimental set-up parameters. The mathematical simulation of the application of the dual focal length lens, for chosen cases presented here, confirmed the accuracy of the proposed procedure.

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