Physicists discover new role for turbulence in fluid flows

A team of physicists has made a groundbreaking discovery regarding the role of turbulence in fluid flows, shedding new light on various phenomena such as the Earth’s liquid core and boiling water. Their research, published in the journal Proceedings of the National Academy of Sciences, focused on turbulent convection, which refers to the movement of fluid when heated from below.

The senior author of the paper, Jun Zhang, a professor of mathematics and physics at New York University and NYU Shanghai, explained that their experiments uncovered intricate interactions between thermal convective flows and a free-moving body. Specifically, they studied Rayleigh–Bénard convection, a type of convection driven by temperature differences.

To conduct their experiments, the researchers utilized a cylindrical container filled with water. They heated the water from the bottom, generating convective flows. These turbulent flows then interacted with a suspended solid, in this case, a rectangular panel that moved freely within the container. This experimental setup allowed the team to gain a deeper understanding of how turbulent flows interact with solid structures.

Zhang pointed out the surprising observation that the system exhibited a certain level of regularity. The flows and the free solid displayed smooth rotations. The team discovered that the turbulent convection-powered flows, in conjunction with the solid, could move in both clockwise and counterclockwise directions. Furthermore, the speed of this co-rotational movement increased with the intensity of the convection. Additionally, the rotation of the flows and the solid sometimes changed direction due to the influence of turbulence.

Zhang highlighted that the inspiration for this research came from the rotation of Earth’s inner core as it interacts with the convective liquid core. The study successfully captured the interaction between a turbulent flow and a freely moving body within that flow. These findings confirm that turbulence can be controlled through interactions with solids. Moreover, the study underscores the significant roles that thermal convection may play within our planet.

Overall, this research opens up new avenues for understanding the behavior of turbulent flows and their interactions with solid objects. The findings have implications for various fields, ranging from geophysics to engineering, and offer fresh insights into the fundamental processes occurring within our planet.

Source: New York University

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