Researchers at the University of Warwick [U.K.] have been inspired by the unique movement of trembling aspen leaves to devise an energy harvesting mechanism that could power weather sensors in hostile environments and could even be a back-up energy supply that could save and extend the life of future Mars rovers.
University of Warwick third year engineering undergraduates have in recent years been set the task of the examining the puzzle of why Aspen leaves quiver in the presence of a slightest breeze. University of Warwick Engineering researchers Sam Tucker Harvey, Dr Igor A. Khovanov, and Dr Petr Denissenko were inspired to look more closely at this task they were annually setting for their students and to take the phenomenon one step further.
They decided to investigate whether the underlying mechanisms that produce the low wind speed quiver in Aspen leaves could efficiently and effectively generate electrical power, simply by exploiting the wind generated mechanical movement of a device modelled on the leaf. They have today 18th March 2019 published the answer to that question as a paper entitled “A Galloping Energy Harvester with Flow Attachment” in Applied Physics Letters and the answer is a resounding yes. (…)
Dr Petr Denissenko further noted that one future application could be as a backup power supply for future Mars landers and rovers.
“The performance of the Mars rover Opportunity far exceeded its designers’ wildest dreams but even its hard working solar panels were probably eventually overcome by a planetary-scale dust storm. If we could equip future rovers with a backup mechanical energy harvester based on this technology, it may further the lives of the next generation of Mars rovers and landers.”
The key to Aspen leaves’ low wind but large amplitude quiver isn’t just the shape the leaf but more importantly relates to the effectively flat shape of the stem.
The University of Warwick researchers used mathematical modelling to come up with a mechanical equivalent of the leaf. They then used a low speed wind tunnel to test a device with a cantilever beam like the flat stem of the Aspen leaf, and a curved blade tip with a circular arc cross section acting like the main leaf… [More at links]