A study of radial-flow turbomachinery blade vibration measurements using Eulerian laser Doppler vibrometry

2014 ◽  
Author(s):  
A. J. Oberholster ◽  
P. S. Heyns
Keyword(s):  
Radial Flow ◽  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Blade Vibration ◽  
Vibration Measurements

scholarly journals Rotor Vibration Measurements Using Laser Doppler Vibrometry: Essential Post-Processing for Resolution of Radial and Pitch/Yaw Vibrations

2005 ◽  
Vol 128 (1) ◽  
pp. 8-20 ◽  
Author(s):  
Ben J. Halkon ◽  
Steve J. Rothberg
Keyword(s):  
Measurement Errors ◽  
Laser Doppler ◽  
Post Processing ◽  
Rotor Vibration ◽  
Laser Doppler Vibrometry ◽  
Vibration Measurements ◽  
Engine Vibration ◽  
Major Application ◽  
The Individual ◽  
First Time

Laser Doppler vibrometry is now a well established technique enabling noncontact vibration measurements in the most challenging of environments. Rotor vibration measurements are often highlighted as a major application of laser vibrometers due to their noncontact operation and inherent immunity to shaft runout. In such measurements, resolution of the individual axial and torsional vibration components is possible via particular arrangement of the laser beam(s). Resolution of the radial or pitch/yaw vibration components, however, can only be achieved by essential post-processing of the data from simultaneous orthogonal measurements. This paper describes the principle and rigorous examination of a novel, dedicated resolution algorithm enabling, for the first time, real-time post-processing of the outputs from standard commercial instruments. The system performed well, even in the presence of noise and other typical measurement errors, and was implemented successfully in an engine vibration study.

Facial Muscle Activity: High-Sensitivity Noncontact Measurement Using Laser Doppler Vibrometry

2021 ◽  
Vol 70 ◽  
pp. 1-10
Author(s):  
Sara Casaccia ◽  
Erik J. Sirevaag ◽  
Mark G. Frank ◽  
Joseph A. O'Sullivan ◽  
Lorenzo Scalise ◽  
...  
Keyword(s):  
Muscle Activity ◽  
High Sensitivity ◽  
Laser Doppler ◽  
Facial Muscle ◽  
Laser Doppler Vibrometry ◽  
Noncontact Measurement

Two-Photon Polymerization Lithography and Laser Doppler Vibrometry of a SU-8-Based Suspended Microchannel Resonator

2015 ◽  
Vol 24 (4) ◽  
pp. 1038-1042 ◽  
Author(s):  
Celso Accoto ◽  
Antonio Qualtieri ◽  
Ferruccio Pisanello ◽  
Carlo Ricciardi ◽  
Candido Fabrizio Pirri ◽  
...  
Keyword(s):  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Two Photon ◽  
Two Photon Polymerization

Use of Laser Doppler Vibrometry for Measuring Flow-Induced Vibration of a Thermowell in a Pipe Flow

2021 ◽  
Author(s):  
Sejong Chun ◽  
Sibok Lee ◽  
Hyewon Yoon
Keyword(s):  
Strain Rate ◽  
Laser Doppler ◽  
Vortex Street ◽  
Rate Measurement ◽  
Flow Induced Vibration ◽  
Laser Doppler Vibrometry ◽  
Karman Vortex Street ◽  
Kármán Vortex Street ◽  
Karman Vortex ◽  
Strain Rate Measurement

Abstract Thermowells with helical strakes are becoming promising to prevent them from fatigue fracture by Kármán vortex street. Many studies suggest various kinds of measurement techniques, including strain rate measurement, acceleration measurement, and high-speed visualization to evaluate the role of Kármán vortex street to the flow-induced vibration. Nevertheless, use of laser Doppler vibrometry has not yet been reported in the literature. This study compared the tip deflection of a thermowell due to the flow-induced vibration by using the laser Doppler vibrometry and the strain rate measurement. The laser Doppler vibrometry could measure the tip deflection directly. On the other hand, the strain rate measurement had to convert the strain rate into the tip deflection through the Euler-Bernoulli beam theory. Measurement equivalence between the laser Doppler vibrometry and the strain rate measurement was discussed with the results of tip deflections of the thermowell.

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