Active Matter, Pattern Formation, Biophysics and Robotic Physics
We have developed finite element simulations, that let us
solve pattern formation models on two-d domains of arbitrary shape.
These help us explore how different active materials
might be used to activate mechanisms through their collective motions.
We have been exploring collective motion in a type of swimming nematode called vinegar eels.
At high concentration they form metachronal waves which can drive flows.
The little worms are about 1mm long and they can be seen by eye.
They are in the class of active matter known as swarmalators because they can be considered to be
self propelled oscillators.
We have been using vibrational motors to explore
low cost locomotion strategies in complex media (slime, sand) that are
not necessarily biologically motivated.
There are not necessarily any similar biological examples.
The locomotion mechanisms can have no external moving parts as they
move because of the motor's recoil.
- Simulations that involve boundaries
Topological defect trains excited by a boundary discontinuity in the two-dimensional complex Ginzburg-Landau equation
- Collective phenomena in swimming nematodes:
On directional phase oscillator models for metachronal wave formation
on arxiv ,
in Phys Rev E
It is surprisingly difficult to find models that robustly give collective waves even though biological systems seem to be able to do this effortlessly!
- We measure circulation in a drop that is caused by vinegar eels that are collectively organized
in a metachronal wave,
on arxiv ,
in Phys Rev E
-
Metachronal waves in concentrations of swimming Turbatrix aceti nematodes and an oscillator chain model for their coordinated motions
arxiv ,
in Phys Rev E
Above is an animation based on an oscillator chain model for
the vinegar eels involved in the metachronal wave.
Also see video
- Anton's paper! (It is on the cover of "Soft Matter")
Synchronized oscillations in swarms of nematode Turbatrix aceti
arxiv ,
Soft matter
-
Using simulations, we explore collective phenomena for aligning self-propelled particles.
The most interesting
of the states we find is when the boundary becomes ruffled.
Boids in a Loop: Self-propelled particles within a flexible loop boundary, arXiv,
in Phys Rev E
A simulation can be viewed here:
Javascript simulation ,
with code available here:
code on github
- A coin vibrational motor powered hopper that can hop
across granular media. It turns out
that aerodynamics is important!
A Light-weight High Froude Number Vibrational Motor Powered Recoil Robot that Hops Rapidly Across Granular Media
published in the Journal of Mechanisms and Robotics
Click on this image to see high speed videos of the mechanism
hopping on poppy seeds
-
The vibration causes streaming in a fluid and if you break the rotational
symmetry the motor can swim! This paper illustrates a novel and low cost
robotic swimmer at Low Reynolds number (in glycerin) that has no external moving parts.
A coin vibrational motor swimming at low Reynolds number,
published in Regular and Chaotic Dynamics, 2016, Vol. 21, No. 7-8, pp 902-917.
Click on the figure to see the movie!
Showing the glycerin velocity field in the frame of the swimming motor.