Vortex induced vibration (VIV) is a type of fluid-structure interaction (FSI) problem which means any change in the fluid flow affects the structure and vice versa. Thus, all the fluid flow parameters, e.g. flow velocity profiles, vortex shedding shapes, and corresponding frequencies, and structural dynamic parameters, e.g. the structure body natural frequency, the oscillation amplitude, frequencies, and forces in lateral and transverse directions, have to be investigated simultaneously. There is still a lack of studies considering all parameters which may be due to the difficulties to measure the fluid flow and structure deformation simultaneously.  Also, the research studies for different measurements techniques for FSI parameters in hydrodynamics are still lacking. Finally, three-dimensional FSI benchmarks for numerical validation studies are still lacking. This leads to the motivation of this dissertation to investigate VIV for a cantilever circular cylinder in a water circulation channel.
 
 
The 3D Digital Image Correlation (DIC) measurement technique was used to measure response without influencing model properties and the flow field. To assess the suitability of DIC for VIV investigations, results obtained from the conventional technique, using a triaxial accelerometer, were compared.  Additionally, forces and torques were measured directly. Further, VIV of a cantilevered circular Teflon cylinder located in a circulating water channel was investigated.  For differing reduced velocities, cylinder accelerations, displacements, and forces acting on the cylinder in the lateral and transverse directions were measured. Vortex shedding frequencies were compared with cylinder response frequencies in the lateral and transverse directions. Additionally,   vortex typologies in the wake of a Teflon cantilevered circular cylinder were investigated and analysed using Particle Image Velocimetry (PIV) technique.  The the shed vortex patterns in the cylinder wake were visualised and captured at three spanwise planes at 25 %, at 50 % , and at 95 % of cylinder height. Different vortex shedding modes, and the hybrid mode of different vortex shedding types along the cylinder’s span were captured. The associated Strouhal numbers were calculated for different reduced velocities estimated with the PIV technique and compared with those obtained by the a Laser Doppler Velocimetry (LDV) technique.

For numerical investigations, two function objects were implemented in open C++ library OpenFOAM, able to simulate the FSI of a circular cylinder in one and two degrees of freedoms. Applying these function objects, a numerical validation of a low mass ratio cylinder was carried out. At the end, the lock-in case of vortex-induced vibration of an oscillating circular cylinder in a circulating water channel subjected to a fluid flow in water channel was investigated. The coupled dynamic inline and transverse response of the cylinder was calculated from numerical simulation and compared to the measured result.