Experimental data of the space ratio influence on the excitation frequencies of one cylinder free to vibrate in tandem arrangement

Published: 29 December 2021| Version 1 | DOI: 10.17632/33rf3kffb2.1
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Description

Data result from careful measurements with accelerometers in an aerodynamic channel to study the influence of the space ratio on the flow-induced vibration of cylinders in tandem arrangement with one fixed and with one cylinder free to vibrate. The Reynolds number for the tested cases ranged between 11400 and 26000, based on one cylinder diameter, the kinematic viscosity at the environmental conditions of the laboratory, and reference velocity from the Pitot tube. The test section is assembled with smooth cylinders with 25.1 mm diameter in the tandem arrangement and an L/D-ratio of 1.26, 1.4, 1.6, and 3.52. One of the cylinders is free-to-vibrate in the transversal direction attached to two blades that allow variating the length to change the stiffness. In all studied cases, the blockage ratio is 13.01 %. The assembly of the cylinder free to vibrate is the same used in Neumeister et al. (2021 a) and Neumeister et al. (2021 b). The tested cases present the nomenclature indicating that the case SC corresponds to a single-cylinder; FL means that the first cylinder is free to vibrate and SL means that the second cylinder is free to vibrate. The mass-damping parameters were equal for all tested cases. The mass ratio was m*=608, the damping ratio ζ = 0.03 and the natural frequencies are fn1 = 7.8Hz and fn2 = 21.5 Hz. The acceleration of the cylinder free to vibrate is the monitored variable. The measurements were executed with accelerometers ADXL 335 with an acquisition frequency of 1 kHz with an anti-aliasing low pass filter at 0.3 kHz. Data acquisition was executed employing an A/D board 16bits NI USB-9162. The acceleration results are presented through the values obtained during the data acquisition for each case tested. The error associated with the acceleration signals is about 7%, and the velocity is between 4% and 8%. The uncertainty associated with the frequency remains around 9%, while that of the reduced velocity is around 10.5%. Data are in .txt format to be read by almost all software with time [s] and acceleration [ m/s²]. References Neumeister, R. F., Petry, A. P., and Möller, S. V. 2021a). Experimental Flow-Induced Vibration Analysis of the Crossflow Past a Single Cylinder and Pairs of Cylinders in Tandem and Side-by-Side. Journal of Pressure Vessel Technology, v. 143(3), p. 031402. Neumeister, R. F., Petry, A. P., and Möller, S. V. 2021 b). Analysis of the coherence between FIV acceleration and flow velocity in a square array tube bank with P/D= 1.26. Nuclear Engineering and Design, v. 373, p. 111016.

Files

Steps to reproduce

The tested cases are organized into three files. The nomenclature indicates that the case SC corresponds to a single-cylinder; FL means that the first cylinder is free to vibrate and SL means that the second cylinder is free to vibrate. Data with time [s] and acceleration [m/s²] are ordered by the case (SC, FL, or SL), then by the L/D-ratio, where L is the distance between centers of the cylinders and D the diameter. A total number of 30 datasets are in .txt format to be read by almost all software. Each data file is identified by the corresponding nomenclature (SC, FL, or SL), the L/-D-ratio, and the reduced velocity (VR). 1-Series SC SC_VR36.txt SC_VR49.txt SC_VR58.txt SC_VR63.txt 2- Series FL/1.26 FL_1.26_VR36.txt FL_1.26_VR49.txt FL_1.26_VR61.txt FL_1.26_VR72.txt 2- Series FL/1.4 FL_1.4_VR37.txt FL_1.4_VR49.txt FL_1.4_VR61.txt FL_1.4_VR72.txt 2- Series FL/1.6 L_1.6_VR37.txt FL_1.6_VR49.txt FL_1.6_VR61.txt FL_1.6_VR72.txt 2- Series FL/3.52 FL_3.52_VR36.txt FL_3.52_VR48.txt FL_3.52_VR60.txt FL_3.52_VR72.txt 3- Series SL/1.26 SL_1.26_VR37.txt SL_1.26_VR48.txt SL_1.26_VR61.txt SL_1.26_VR72.txt 3- Series SL/1.4 SL_1.4_VR49.txt SL_1.4_VR61.txt SL_1.4_VR72.txt 3- Series SL/1. 6 SL_1.6_VR49.txt SL_1.6_VR61.txt SL_1.6_VR72.txt 3- Series SL/3.52 SL_3.52_VR60.txt SL_3.52_VR72.txt

Institutions

Universidade Federal do Rio Grande do Sul

Categories

Fluid Dynamics, Mechanical Vibration

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