Experimental study of vortex-induced vibrations of flexibly mounted cylinder in circulating water tunnel

Abstract

This paper presents the experimental results concerning the vortex-induced vibration phenomena of a flexibly mounted enclosed smooth rigid pipe. The experiment was newly designed and fabricated, utilizing the circulating water tunnel concept. New results on the dynamic response of the vibrating system are shown. The stream flow was generated by using a large displacement volume submersible water tank, controlled through the ABB inverter. The rotation frequency controlled based was implemented in the ABB inverter, and the measurement of stream flow was taken by using a flow rate sensor at the respective pump rotation frequency. The Reynolds number of the experiments ranges from ∼4900 to ∼15,000, and its corresponding reduced velocities, based on the natural frequency in still water, vary up to ∼7. The riser modeled pipe was positioned in vertical direction, and it is flexibly mounted at both ends. The system has low mass ratio and damping coefficient, with the values 1.184 and 0.08, respectively. The mass-damping ratio (m * ζ ) is 0.09472. The results for the bare pipe cylinder in this experimental setup are in good agreement with other measurements found in the literature.

Flow Induced Vibration in Square Cylinder of Various Angles of Attack

“…The percentage error is found to be 9.81%. Similar error percentages were also reported in [23] where up to 11.55% of error percentage was achieved using the same equation. Since the error percentage was less than 20%, the experimental value should be acceptable [24].…”

“…where kTotal is the stiffness of the system while mTotal is the mass of the system. This equation was adopted from previous study of VIV with similar experimental settings [23]. The value obtained for spring stiffness of the system was 119.6 N/m as the springs were attached in parallel.…”

Research on Flow-induced Vibration Response and Energy Conversion performance of Four-cylinder Acquatic Clean Energy Harvesting Device

“…In VIV initial branch, the frequency ratios of four cylinders in numerical simulation are all around the natural frequencies in water. The frequency ratios of four cylinders in experiment all jump to nearly 1.0 when Re=4×10 4 . In VIV upper branch of 1st cylinder, the frequency ratios in simulation are over-predicted.…”

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“…The flow speed of the working section is up to 0.4 m/s. Details of the water tank were given [13]. Fig.…”