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Inverse Energy Cascade and Intermittency in 2D bacterial turbulence

SourceSeminar Date of Publication:Aug 11,2022
08/11 2022 Seminar
  • Title Inverse Energy Cascade and Intermittency in 2D bacterial turbulence
  • Speaker 黄永祥 (厦门大学)
  • Date 2022年8月11日 10:30
  • Venue TencentMeeting:943-348-695
  • Abstract

    The mesoscale turbulence was found experimentally for the active interaction between the bacteria and flow fluid (e.g., water). More precisely, the large-scale coherent flow pattern, e.g., 10 times larger than the bacterial body size was experimentally found at nearly zero Reynolds number. This fascinating phenomenon can be understood in the framework of turbulence, where the kinetic energy is injected into the system via a size of bacterial body length R in a few μms, and is transferred to up scales. In this talk, the scaling behavior of the bacterial turbulence is analyzed experimentally. Our results confirm the existence of the inverse energy cascade, e.g., transferring kinetic energy from small-scale structures to larger ones. Moreover, the intensity of the intermittency correction, i.e., the departure from the pure scaling relation for the high-order moments, is characterized quantitatively in the log-normal framework. Finally, the possible universality of the intermittency correction is discussed as a perspective.


    黄永祥 厦门大学 海洋与地球学院 近海海洋环境科学国家重点实验室 副教授,2002年毕业于上海交通大学,获学士学位,2009年获上海大学、法国里尔大学博士学位。主要从事湍流统计理论及其应用,非线性-非平稳统计方法及其应用研究,曾获2013年欧洲地球科学联盟地球科学中非线性过程部杰出青年科学家奖,在Journal Geophysical Research、Journal of Fluid Mechanics、Physics of Fluids、Physical Review E、Atmospheric Chemistry and Physics、Atmospheric Environment、Journal of Marine Systems等主流期刊发表SCI论文60余篇,并由剑桥大学出版社出版英文专著一部。