Wave Power Generation Using Nonlinear Roll-Pitch Coupling in a Ship

Ansari, M. H.; Yerrapragada, Karthik; Karami, M. Amin

doi:10.1115/smasis2016-9203

Cited by 2 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To avoid the reflection of the waves from the ends of the tank, we use two passive wave absorbers at the two ends of the wave tank [32]. If we do not use wave absorbers, the reflected waves will interfere with the waves in the tank and disturb them and create waves with multiple frequency amplitudes.…”

Section: Methodsmentioning

confidence: 99%

Enhancing power generation of floating wave power generators by utilization of nonlinear roll-pitch coupling

Yerrapragada

Ansari

Karami

2017

Smart Mater. Struct.

Self Cite

View full text Add to dashboard Cite

We propose utilization of the nonlinear coupling between the roll and pitch motions of wave energy harvesting vessels to increase their power generation by orders of magnitude. Unlike linear vessels that exhibit unidirectional motion, our vessel undergoes both pitch and roll motions in response to frontal waves. This significantly magnifies the motion of the vessel and thus improves the power production by several orders of magnitude. The ocean waves result in roll and pitch motions of the vessel, which in turn causes rotation of an onboard pendulum. The pendulum is connected to an electric generator to produce power. The coupled electro-mechanical system is modeled using energy methods. This paper investigates the power generation of the vessel when the ratio between pitch and roll natural frequencies is about 2 to 1. In that case, a nonlinear energy transfer occurs between the roll and pitch motions, causing the vessel to perform coupled pitch and roll motion even though it is only excited in the pitch direction. It is shown that co-existence of pitch and roll motions significantly enhances the pendulum rotation and power generation. A method for tuning the natural frequencies of the vessel is proposed to make the energy generator robust to variations of the frequency of the incident waves. It is shown that the proposed method enhances the power output of the floating wave power generators by multiple orders of magnitude. A small-scale prototype is developed for the proof of concept. The nonlinear energy transfer and the full rotation of the pendulum in the prototype are observed in the experimental tests.

show abstract

Section: Methodsmentioning

confidence: 99%