The 12th International Conference on Hydrodynamics
18 – 23 september 2016, Egmond aan Zee, The Netherlands
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NUMERICAL STUDY OF THE INTERACTION BETWEEN TWO IMMERSED CYLINDERS


Go-down ichd2016 Tracking Number 55

Presentation:
Session: Fluid structural inter-actions I
Room: Room 4
Session start: 10:30 Mon 19 Sep 2016

Zhonglu Lin   zl352@cam.ac.uk
Affifliation: the University of Cambridge

Dongfang Liang   dl359@cam.ac.uk
Affifliation: the University of Cambridge

Ming Zhao   M.Zhao@westernsydney.edu.au
Affifliation: Western Sydney University


Topics: - Fluid-structural interactions and hydroelasticity, - Computational fluid dynamics

Abstract:

The interaction between two adjacent cylinders immersed in fluid is studied numerically by solving the two-dimensional Navier-Stokes (NS) equations using a finite element method (FEM). The two rigid cylinders are immersed in otherwise stationary fluid. One cylinder (C1) undergoes forced vibration that disturbs the fluid, whereas another cylinder (C2), which has one-degree-of-freedom (1DOF), vibrates correspondingly under the action of the imbalanced hydrodynamic force. All the simulations carried out in this study have a constant Reynolds number of 100 and a constant mass ratio of 2.5. Simulations are conducted with 9 initial gap ratios, G, ranging from 0.05 to 3 times of the cylinder diameter, with various forced vibration amplitude A1 and frequency f1 of C1. We find that C2’s amplitude (A2) reaches maximum when C1’s vibration frequency (f1) is approximately 80% of C2’s structural natural frequency (fn). The increase of C1’s amplitude (A1) leads to the rise of C2’s amplitude (A2) but the decrease of its relative amplitude (A2/A1). The increase in A1 also slightly reduces the value of f1 at the maximum A2. In addition, the vibration centre of C1 is observed to shift away from original location in cases with the large gap ratio. The shift becomes increasingly obvious with an increase of A1 and f1. Finally, C2 is found to respond to the vibration of C1 with bigger amplitude in some situations with small gap ratios, which can be interpreted as the occurrence of resonance.