Featured Research

from universities, journals, and other organizations

Optimum inertial self-propulsion design for snowman-like nanorobot

Date:
July 29, 2014
Source:
Springer Science+Business Media
Summary:
A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines. Scale plays a major role in locomotion. Swimming microorganisms, such as bacteria and spermatozoa, are subjected to relatively small inertial forces compared to the viscous forces exerted by the surrounding fluid. Such low-level inertia makes self-propulsion a major challenge. Now, scientists have found that the direction of propulsion made possible by such inertia is opposite to that induced by a viscoelastic fluid.

Streamlines, velocity field, and magnitude of the share of the propelling flow attributed to the low level inertial force, in the case of touching spheres.
Credit: © Nadal et al.

Scale plays a major role in locomotion. Swimming microorganisms, such as bacteria and spermatozoa, are subjected to relatively small inertial forces compared to the viscous forces exerted by the surrounding fluid. Such low-level inertia makes self-propulsion a major challenge. Now, scientists have found that the direction of propulsion made possible by such inertia is opposite to that induced by a viscoelastic fluid.

Related Articles


These findings have been published in The European Physical Journal E by Franηois Nadal from the Alternative Energies and Atomic Energy Commission (CEA), in Le Barp, France, and colleagues. This study could help to optimise the design of self-propelled micro- and nanoscale artificial swimming machines to improve their mobility in medical applications.

The authors focus on two joined spheres of different radii-dubbed a dumbbell-rotating in a model fluid. They first use simulation to study the effect of a small-scale inertial force on the dumbbell's propulsion. They then compare it with results from theoretical calculations describing locomotion.

They demonstrate that despite the geometrical asymmetry, such a dumbbell cannot self-propel in a pure Newtonian fluid-which is a model fluid whose viscosity does not change with its flow rate-in the absence of inertia. This is because of the underlying laws of physics. If a dumbbell rotating in the counter-clockwise direction propels upwards in the absence of inertia, it would have to move downwards when rotating in the counter-clockwise direction. As both problems are mirror-image symmetric from each other, their propulsion should occur in the same direction and thus without inertia a rotating dumbbell cannot self-propel.

Furthermore, the study shows that a rotating dumbbell propels with the large sphere due to inertial forces in the fluid and the small sphere ahead in a pure viscoelastic fluid. With this in mind, the authors then derive the optimal dumbbell geometry for a self-propelling small-scale swimmer.


Story Source:

The above story is based on materials provided by Springer Science+Business Media. Note: Materials may be edited for content and length.


Journal Reference:

  1. Franηois Nadal, On Shun Pak, LaiLai Zhu, Luca Brandt, Eric Lauga. Rotational propulsion enabled by inertia. The European Physical Journal E, 2014; 37 (7) DOI: 10.1140/epje/i2014-14060-y

Cite This Page:

Springer Science+Business Media. "Optimum inertial self-propulsion design for snowman-like nanorobot." ScienceDaily. ScienceDaily, 29 July 2014. <www.sciencedaily.com/releases/2014/07/140729115334.htm>.
Springer Science+Business Media. (2014, July 29). Optimum inertial self-propulsion design for snowman-like nanorobot. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/07/140729115334.htm
Springer Science+Business Media. "Optimum inertial self-propulsion design for snowman-like nanorobot." ScienceDaily. www.sciencedaily.com/releases/2014/07/140729115334.htm (accessed October 25, 2014).

Share This



More Matter & Energy News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) — IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) — A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) — Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) — A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins