The wake induced vibration of a structure placed in a wake is experimentally investigated with two circular shaped by cylinders in wind tunnel.
The parameters chose in this experiment include the free stream wind velocity and the position of the downstream cylinder placed in the upstream generated wake.
The range of Reynolds number covered in this experiment is about $2\times10^4 - 6\times10^4$, and the reduced velocity is about 4.0 - 11.0.
Vibration amplitude of downstream cylinder decrease as the distance between two cylinders increase. When the two cylinders are placed closely (about within 10 cylinder diameters), it was found that downstream cylinder vibration amplitude is a function of the distance. It can be said as a result of experiment, downstream cylinder vibration is mainly due to vortex sheddings from both cylinders and local flow velocity in the wake.
It seems that the largest downstream cylinder vibration amplitude occurs when the vortices from upstream cylinder superimpose on downstream generated vortices or match with those in the above mentioned range of Reynolds number and reduced velocity.
It also seems that the downstream induced vortices are strongly influenced by the so called local wind velocity in the wake.