Ferrofluid surface simulations go more than skin deep

January 10, 2021

The spiky structure that erupts from the smooth surface of a ferrofluid when a magnet is brought close can be predicted more accurately than previously thought. KAUST researchers have shown that computational algorithms can calculate the ferrofluid's bristling response to a magnet by simulating only the liquid's surface layer.

Ferrofluids are liquid suspensions of iron-based particles that behave like a regular fluid, but once a magnet is present, the ferrofluid rapidly shape-shifts to form spikes that align with the magnetic field. Originally developed by NASA, ferrofluids have numerous uses ranging from advanced electronics to nanomedicine and have the potential for even broader use, if their magnetic responses could be predicted more accurately.

Dominik Michels and his team are applying computer simulations to model ferrofluid behavior. "Our aim is to develop an efficient and accurate algorithm to simulate the macroscopic shapes and dynamic movement of ferrofluids," says Libo Huang, a Ph.D. student in Michels' team.

Recently, looking at the wider field of fluid simulation, the team has shown that the concept of simulating fluid motion by considering only the liquid's surface can be adapted to ferrofluids.

"While the surface-only liquid simulation provides a platform for fluid simulation, its extension to ferrofluids is significant," Huang says. To model a fluid's behavior based only on its surface, the liquid must respond to inputs in a simple linear fashion. Most ferrofluids have a complex non-linear response to a magnetic field.

However, the team showed that as long as the magnetic field is not too strong, the response is close to linear, enabling them to perform a surface-only calculation of the magnetic field response.

In the simulation, the researchers represented the liquid surface as a series of triangles, Huang explains. "The representation of ferrofluids as surface triangles allowed us to accurately estimate the curvature of the liquid interface as well as the interface position," he says. The spike structure can be simulated by calculating the interplay between the magnetic force and the liquid's surface tension.

Considering only the fluid's surface, rather than its entire volume, made the simulation far more computationally efficient, enabling more accurate simulation of the complex ferrofluid behavior. "We were able to reproduce the distance between spikes of the real fluid's spike pattern in an accurate quantitative fashion," Michels says. "We could simulate much more complex dynamic motion."

The next step could be to extend the work to include nonlinear magnetic relationships, Huang says.
-end-


King Abdullah University of Science & Technology (KAUST)

Related Magnetic Field Articles from Brightsurf:

Investigating optical activity under an external magnetic field
A new study published in EPJ B by Chengping Yin, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China, aims to derive an analytical model of optical activity in black phosphorous under an external magnetic field.

Magnetic field and hydrogels could be used to grow new cartilage
Instead of using synthetic materials, Penn Medicine study shows magnets could be used to arrange cells to grow new tissues

Magnetic field with the edge!
This study overturns a dominant six-decade old notion that the giant magnetic field in a high intensity laser produced plasma evolves from the nanometre scale.

Global magnetic field of the solar corona measured for the first time
An international team led by Professor Tian Hui from Peking University has recently measured the global magnetic field of the solar corona for the first time.

Magnetic field of a spiral galaxy
A new image from the VLA dramatically reveals the extended magnetic field of a spiral galaxy seen edge-on from Earth.

How does Earth sustain its magnetic field?
Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles.

Scholes finds novel magnetic field effect in diamagnetic molecules
The Princeton University Department of Chemistry publishes research this week proving that an applied magnetic field will interact with the electronic structure of weakly magnetic, or diamagnetic, molecules to induce a magnetic-field effect that, to their knowledge, has never before been documented.

Origins of Earth's magnetic field remain a mystery
The existence of a magnetic field beyond 3.5 billion years ago is still up for debate.

New research provides evidence of strong early magnetic field around Earth
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed.

Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.

Read More: Magnetic Field News and Magnetic Field Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.