The response of riser with vibration damper energy harvesting device under coupling interference

A riser vibration damper energy harvesting device (VDEHD) was proposed to mitigate fatigue damage caused by vortex-induced vibrations (VIV) in marine riser structures while simultaneously harnessing the energy generated by VIV. The experiment was conducted to study the vibration suppression and energy conversion effects of a VDEHD on downstream risers (DRs) under conditions of various wake interferences. The results indicate that the device effectively suppresses vibrations and harvests energy. It efficiently converts the vibration energy from the riser into electrical output. VDEHD usually produces induced current when the reduced velocity (Ur) is greater than 9.72, and the energy conversion efficiency of VDEHD gradually increases with the increase in reduced velocity, and the maximum energy conversion efficiency can reach 34.51%. Under wake interference conditions, the spacing ratio (S/D) is the key factor of optimal design, with the increase in the spacing ratio, the influence of the upstream riser wake interference on the downstream riser decreases, and the vibration suppression efficiency of VDEHD shows an upward trend. However, this reduced riser vibration will also lead to a decrease in the energy conversion efficiency of VDEHD.