Physicists make interesting discovery in Earth's core-inspired study

A group of physicists discovered that convection currents become "well-behaved" in an experiment inspired by the workings of the Earth's core.
Christopher McFadden
The experiment was inspired by the workings of the Earth's inner core.


A new study published in the journal Proceedings of the National Academy of Sciences reports on a discovery that might have found a novel way of using a specific type of convection. Called Rayleigh–Bénard convection, this discovery can help us better understand how fluids flow when heated from below. This could have some exciting applications in the real world, including making discoveries in how the Earth's liquid core behaves or how molecules move in boiling water.

In case you are unaware, Rayleigh-Bénard convection occurs when a fluid is heated from below and cooled from above; it can result in visible patterns and motion. This phenomenon creates convection cells as the heated fluid rises, becomes less dense, then cools and sinks back down. The interplay between buoyancy and heat transfer gives rise to distinct patterns in the cells, which vary depending on factors like temperature difference and container dimensions. Rayleigh-Bénard convection has practical applications in fields such as meteorology and engineering, where it influences heat transfer and fluid dynamics.

“Our experiments reveal intricate movements between a free-moving body and thermal convective flows,” says Jun Zhang, a professor of mathematics and physics at New York University and NYU Shanghai, the paper’s senior author.

The researchers conducted experiments at NYU Shanghai's Joint Research Institute using a cylindrical container filled with water.

They heated the container from the bottom, creating convective flows that interacted with a suspended solid (a rectangular panel) that moved freely inside the container. This allowed the researchers to gain a better understanding of how turbulent flows interact with solid structures.

“Surprisingly, the system becomes somewhat well-behaved,” notes Zhang. “We observed a smooth rotation of the flows and the free solid,” he added.

According to their findings, the movement of turbulent convection-powered flows in tandem with solids can occur in two directions - clockwise and counterclockwise. The speed of co-rotation increases with the intensity of the convection. Additionally, the rotation has the ability to switch directions at times, which is attributed to the presence of turbulence.

“The research, inspired by the rotation of Earth’s inner core as it interacts with the convective liquid core, captures the interaction between a turbulent flow and a freely moving body within the flow,” explains Zhang. “The findings confirm that turbulence can be tamed by interacting with solids. It also reminds us that the power of thermal convection might play more important roles inside our planet Earth,” he added.

You can read the study for yourself in the journal Proceedings of the National Academy of Sciences.

Study abstract:


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