Trembling aspen leaves could save future Mars rovers – ScienceDaily

Third year engineering students from the University of Warwick have been instructed in recent years to examine the puzzle that explains why Aspen leaves tremble in the presence of the slightest breeze . Researchers Sam Harvey Tucker, Igor A. Khovanov and Petr Denissenko, researchers at the University of Warwick Engineering, were inspired by the idea of ​​taking a closer look at this task that they set themselves each year for their students and to push the phenomenon even further.

They decided to investigate whether the underlying mechanisms that produce the quiver at low wind speed in Aspen leaves could efficiently generate electrical energy simply by exploiting the mechanical motion generated by the wind of a device modeled on the sheet. Today, March 18, 2019, the answer to this question was published in the form of a document entitled "A galloping energy recuperator with flow attachment" in Applied Physics Letters and the answer is a resounding yes.

Sam Tucker Harvey, an engineering researcher from the University of Warwick, lead author of the paper, said:

"The most interesting thing about this mechanism is that it provides a mechanical way to generate energy without using bearings, which can stop working in extremely cold, heated, dusty or dusty environments." the potential energy that can be generated is small, it would be more than enough to power stand-alone electrical devices, such as wireless sensor networks, which could be used for applications such as automatic weather detection. in remote and extreme environments. "

Dr. Petr Denissenko further noted that a future application could be a source of emergency power for future landers and Mars rovers.

"The performance of the robot rover Opportunity far exceeded the craziest dreams of its designers, but even its hard-working solar panels were probably eventually overcome by a dust storm on a planetary scale. Future rovers of an emergency energy recuperator based on this technology, this could improve the lives of the next generation of rovers and Mars landers. "

The key to the weak wind of Aspen leaves, but a quiver of great amplitude is not limited to the shape of the leaf but mostly relate to the actually flat shape of the stem.

Researchers at the University of Warwick used mathematical modeling to obtain a mechanical equivalent of the leaf. They then used a low velocity wind tunnel to test an apparatus with a cantilever beam similar to the flat stem of the aspen leaf and a curved blade end with an arcuate cross-section serving as the main leaf.

The blade was then oriented perpendicular to the direction of flow, allowing the harvester to produce self-sustaining oscillations at unusually low wind speeds such as aspen leaf. The tests showed that the air flow was fixed on the rear face of the blade when the velocity of the blade was sufficiently high, acting in a manner more similar to a bearing surface rather than the bluff bodies studied in the context of wind energy recovery.

In nature, the tendency of the leaf to shake is also reinforced by the tendency of the thin stalk to twist in the wind in two different directions. However, researchers who modeled and tested the tests found that they did not need to duplicate the additional complexity of an additional degree of motion in their mechanical model. Simply reproducing the basic properties of the flat rod as a cantilever beam and curved blade end with an arcuate cross-section behaving like the main sheet was enough to create sufficient mechanical movement to harvest power.

Researchers will then examine power generation technologies based on the mechanical movements that could best exploit this device and the best way to deploy them in bays.

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