Los físicos han descubierto un nuevo aspecto de la convección turbulenta, demostrando que puede hacer que un sólido que se mueve libremente dentro del fluido gire en dos direcciones, a veces cambiando debido a la turbulencia. Esta investigación, que tiene implicaciones para comprender los flujos de fluidos desde el núcleo de la Tierra hasta el agua hirviendo, también destaca el papel clave que puede desempeñar la convección térmica dentro de la Tierra y el potencial de control de la turbulencia mediante la interacción con los sólidos.

Los flujos turbulentos dan un giro sorprendente a un experimento inspirado en el núcleo de la Tierra.

Un equipo de físicos ha descubierto un nuevo papel para un tipo específico de turbulencia: un descubrimiento que arroja luz sobre los flujos de fluidos desde el núcleo líquido de la Tierra hasta el agua hirviendo.

La investigación, publicada en la revista Anales de la Academia Nacional de Cienciascentrado en la convección turbulenta: el movimiento del fluido cuando se calienta desde abajo.

“Nuestros experimentos revelan movimientos intrincados entre un cuerpo en movimiento libre y flujos convectivos térmicos”, dice Jun Zhang, profesor de matemáticas y física en la[{» attribute=»»>New York University and NYU Shanghai, the paper’s senior author.

The study, which also included Kaizhe Wang, a researcher in NYU’s Department of Physics, focused specifically on Rayleigh–Bénard convection—a type of convection driven by temperature differences.

A recent experimental study, inspired by the super-rotation of the Earth’s solid core, shows when turbulence flows contained in a cylinder interact with a free body a surprisingly smooth rotation is observed. The red (warm) and blue (cold) ribbons represent water flows. Credit: Kaizhe Wang and Jun Zhang

In their experiments, conducted in the Joint Research Institute of NYU Shanghai, the paper’s authors used a cylindrical container filled with water, then heated it from the bottom, creating convective flows. The resulting turbulent flows interacted with a suspended solid (a rectangular panel) that moved freely inside the container—a setting that allowed the researchers to better study how turbulent flows interact with solid structures within.

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

Their results showed that turbulent convection-powered flows, together with the solid, can move in two directions—one clockwise and the other counterclockwise—with the co-rotational speed increasing with the intensity of the convection. More than that, their rotation can sometimes switch directions, caused by the 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.”

Reference: “Persistent corotation of the large-scale flow of thermal convection and an immersed free body” by Kaizhe Wang and Jun Zhang, 15 May 2023, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2217705120