Inspired by the superrotation of the Earth's solid core, we investigate the dynamics of a free-rotating body as it interacts with the large-scale circulation (LSC) of the Rayleigh-Bénard thermal convection in a cylindrical container. A surprising and persistent corotation of both the free body and the LSC emerges, breaking the axial symmetry of the system. The corotational speed increases monotonically with the intensity of thermal convection, measured by the Rayleigh number Ra, which is proportional to the temperature difference between the heated bottom and cooled top. The rotational direction occasionally and spontaneously reverses, occurring more frequently at higher Ra. The reversal events follow a Poisson process; it is feasible that flow fluctuations randomly interrupt and reestablish the rotation-sustaining mechanism. This corotation is powered by thermal convection alone and promoted by the addition of a free body, enriching the classical dynamical system.
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http://dx.doi.org/10.1073/pnas.2217705120 | DOI Listing |
Soft Matter
January 2025
Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India.
This work estimates Michaelis-Menten kinetics parameters for nutrient transport under varying flow rates in the soft roots of Indian mustard () using a plant fluidic device. To find the metallic components within the roots, inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed. The flow rate-dependent metabolic changes were examined using Raman spectral analysis.
View Article and Find Full Text PDFLangmuir
January 2025
College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin 150040, China.
Solar-driven interfacial evaporation technology is regarded as a promising strategy for global freshwater shortage owing to its green and sustainable desalination process. Graphene aerogel (GA) is widely utilized in the design of solar-driven steam generation systems due to its excellent photothermal conversion efficiency and broad spectral absorption. Given the significant impact of hydrophilicity and thermal insulation on the performance of evaporators, nitrogen doping in the graphene structure not only effectively enhances its wettability but also allows for moderate tuning of its thermal conductivity, thereby optimizing the overall performance of the evaporator.
View Article and Find Full Text PDFHeliyon
January 2025
Biomedical Engineering Department, College of Engineering and Technologies, Al-Mustaqbal University, Hillah, Iraq.
The optimization of heat transfer in various engineering applications, such as thermal management systems and energy storage devices, remains a crucial challenge. This study aims to investigate the potential of Casson-based Cu-HO nanofluids in enhancing free convection heat transfer within complex geometries. The research examines the free convection heat transfer and fluid flow characteristics of a Casson-based Cu-HO nanofluid within a semi-parabolic enclosure that includes a wavy corrugated cylinder.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Thermal energy harvesting for high-speed moving objects is particularly promising in providing an efficient and sustainable energy source to enhance operational capabilities and endurance. Thermoelectric (TE) technology, by exploiting temperature gradients between a heat source and ambient temperature, can provide a continuous power supply to such systems, reducing the reliance on conventional batteries and extending operation times. However, the integrated thermoelectric generator (TEG) system design research is far behind materials development.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
A practical approach to augment the heat transmission effectiveness of thermo-fluid systems involves the utilization of nanofluids instead of traditional fluids. The present investigation compares different models for determining nanofluids' volumetric thermal expansion coefficient with the experimental findings. A benchmark problem of free convection is chosen to assess the accuracy of the existing models.
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