The global instantaneous power injected in a turbulent shear flow is investigated. A conditional averaging technique reveals the complete energetic transfer scenario of the intense vorticity filaments, which were visualized by Douady, Couder, and Brachet [Phys. Rev. Lett. 67, 983 (1991)]. It is found that during their existence filaments store a significant part of the turbulent kinetic energy. This energy is dissipated during the destruction phase of filaments. The total energy transferred to small scales due to filaments is quantified on the basis of a global flow visualization.
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http://dx.doi.org/10.1103/PhysRevE.67.027301 | DOI Listing |
Nat Commun
January 2025
Key Laboratory of Physical Oceanography and Frontiers Science Center for Deep Ocean Multispheres and Earth System/Academy of Future Ocean, Ocean University of China, Qingdao, China.
The Gulf Stream region (GSR) represents an area of robust oceanic eddies, active hurricanes, and more importantly, frequent encounters between the two phenomena. However, the direct impact of the intense storms on the eddy field has seldom been comprehensively examined. Here based on a multi-year analysis of eddy energy changing rate, we demonstrate that hurricanes enhance cyclonic eddies but weaken anticyclonic ones by injecting potential vorticity into the ocean.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Optical vortices possess a helical phase wavefront with central phase dislocation and orbital angular momentum. We demonstrated three-dimensional microstructure formation using a femtosecond optical vortex beam. Two-photon polymerization of photocurable resin was induced by long-term exposure, resulting in the fabrication of cylindrical structures.
View Article and Find Full Text PDFNanophotonics
March 2024
School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, OK 74078, USA.
Sci Rep
November 2024
Univ. Grenoble Alpes, CNRS, Grenoble INP, LEGI, 38000, Grenoble, France.
The most prominent and persistent feature of the eastern Mediterranean Levantine Basin (LB) is the warm anticyclonic Cyprus Eddy (CE) located above the Eratosthenes Seamount (ESM). This eddy periodically couples with two smaller cyclonic and anticyclonic eddies, the South Shikmona Eddy (SSE) and North Shikmona Eddy (NSE), which form downstream. The reason for the zonal drift of the CE center and the formation mechanism of the CE, SSE and NSE is largely debated today, yet the upwelling and biological productivity of the LB can be strongly impacted by the local dynamics.
View Article and Find Full Text PDFIn this paper, the circular Bessel Gaussian beams (CBGBs) carrying power-cotangent-phase vortices are firstly introduced, whose propagation dynamics are explored theoretically and experimentally. The number of spiral lobes, rotation direction, rotation angle, and shape of the new type of beam can be flexibly modulated by controlling multiple parameters of power-cotangent-phase vortices. Accordingly, the effect of multiple beam parameters on abruptly autofocusing ability is quantified and compared by using the K-value curve that is described by ratio Im/I, where Im and I correspond to the maximum intensities at different propagation distance and the initial plane, respectively.
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