Abstract
A fibre Bragg grating (FBG) sensor was proposed as an alternative to strain gauges to measure the strain ε of a vibrating cylinder in a uniform cross flow. In order to validate the measurements of the FBG sensor, the transverse fluctuating bending displacement Y of the cylinder was also measured using a laser vibrometer. The two measurements were found to be consistent in terms of the natural frequency of the fluid-structure system and the vortex shedding frequency. The spectral coherence between ε and Y at the same point of the cylinder attains 1 at these frequencies, thus indicating a near perfect correlation between the two quantities. When the transverse bending displacement is small, the measured ε and Y are linearly related. Therefore, the results indicate that the FBG sensor can be used with confidence to measure the fluctuating strain arising from the vortex-induced forces on a structure in a uniform cross flow. As such, it can be used in conjunction with a laser Doppler anemometer to study fluid-structure interactions in flow-induced vibration problems. Furthermore, it is expected that the FBG sensor, because of its physical uniqueness, will have an important role to play in the study of fluid-structure interaction problems with multiple structures arranged in an array.
Original language | English |
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Pages (from-to) | 359-367 |
Number of pages | 9 |
Journal | Experiments in Fluids |
Volume | 27 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Sept 1999 |
ASJC Scopus subject areas
- Computational Mechanics
- Mechanics of Materials
- General Physics and Astronomy
- Fluid Flow and Transfer Processes