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COBEM 2021
26th International Congress of Mechanical Engineering
Flow-Induced Vibrations of the Downstream Cylinder in a Tandem Arrangement Based on a Wake Oscillator
Submission Author:
Rafael Feher , SP
Co-Authors:
Rafael Feher, Juan Pablo Julca Avila
Presenter: Rafael Feher
doi://10.26678/ABCM.COBEM2021.COB2021-0680
Abstract
When two cylindrical structures are vibrating close to each other, such as risers, power transmission lines and heat exchanger tubes, they experience higher amplitudes of vibration and wider synchronization ranges when compared to the response obtained for a single cylindrical structure. We present a modified wake oscillator model to predict Flow-Induced Vibrations of the downstream cylinder, i.e., the cylinder behind the cylinder exposed to the freestream fluid flow, in a tandem arrangement with two identical smooth rigid cylinders elastically mounted for reduced velocities lower than 12. The upstream cylinder was always fixed, while the downstream cylinder was allowed to vibrate. Spacing ratios varying from 0.3 to 3.2 were simulated and compared with experimental data. For this purpose, an existing vortex-induced vibration model based on a wake oscillator was modified to account for the effects of varying spacing ratios in the downstream cylinder response. Two empirical coefficients were added in the wake oscillator equation and one in the structure oscillator equation of the downstream cylinder to model the wake-induced vibrations generated by the interference between the two cylinders. The model was able to predict the maximum amplitudes of vibration for the downstream cylinder when varying the spacing ratio and results shows to be in good agreement with experimental data.
Keywords
Flow-induced Vibrations, wake-oscillator model, fluid-structure interaction
