scholarly journals Non-contact measurement of particle velocity distribution of ultrasonic waves along an elastic bar using laser Doppler velocimetry.

1994 ◽  
Vol 15 (5) ◽  
pp. 339-344 ◽  
Author(s):  
Moojoon Kim ◽  
Hiroshi Kanai ◽  
Noriyoshi Chubachi
Keyword(s):  
Velocity Distribution ◽  
Particle Velocity ◽  
Laser Doppler Velocimetry ◽  
Ultrasonic Waves ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Contact Measurement ◽  
Elastic Bar

scholarly journals Development of Miniaturized Fiber-Optic Laser Doppler Velocimetry Sensor for Measuring Local Blood Velocity: Measurement of Whole Blood Velocity in Model Blood Vessel Using a Fiber-Optic Sensor with a Convex Lens-Like Tip

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Tsutomu Tajikawa ◽  
Wataru Ishihara ◽  
Shimpei Kohri ◽  
Kenkichi Ohba
Keyword(s):  
Velocity Distribution ◽  
Laser Doppler Velocimetry ◽  
Fiber Optic ◽  
Flow Direction ◽  
Blood Velocity ◽  
Laser Doppler ◽  
Fiber Optic Sensor ◽  
High Signal ◽  
Doppler Velocimetry ◽  
Injection Needle

A miniaturized fiber-optic laser Doppler velocimetry sensor has been developed to measure the local blood velocity in vivo. The laser beam emitted from the sensor tip can be focused at any distance between 0.1 and 0.5 mm from the tip. Consequently, the sensor has a sufficiently high signal-to-noise ratio to measure the local velocity in almost any opaque fluid, including blood. The sensor head is inserted in an injection needle or a catheter tube. In the former case, it is inserted at an angle to the wall of a vessel and is scanned across the vessel to measure the velocity distribution. In the latter case, it is aligned parallel with the flow in a vessel. For all flows of whole human blood, whole caprine blood, and 69% hematocrit of bovine blood, the velocity distribution across the vessel could be measured very accurately. The insertion angle of the fiber into the flow significantly affects the measurement accuracy; an angle of about 50° is suitable when an injection needle is used. When a catheter is employed, an insertion direction opposite to the flow direction is better than parallel to the flow due to the generation of a wake behind the fiber.

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