| Title | Evolution of two counter-rotating vortices in a stratified turbulent environment |
| Authors | Bin, Yuanwei Yang, Xiang I. A. Yang, Yantao Ni, Rui Shi, Yipeng |
| Affiliation | Penn State Univ, Mech Engn, University Pk, PA 16802 USA Peking Univ, Coll Engn, State Key Lab Turbulence & Complex Syst, Beijing 100871, Peoples R China Peking Univ, Coll Engn, Dept Mech & Engn Sci, Beijing 100871, Peoples R China Pilot Natl Lab Marine Sci & Technol Qingdao, Joint Lab Marine Hydrodynam & Ocean Engn, Qingdao 266299, Shandong, Peoples R China Johns Hopkins Univ, Mech Engn, Baltimore, MD 21218 USA |
| Keywords | DIRECT NUMERICAL SIMULATIONS STRAIGHT VORTEX FILAMENT LARGE-EDDY SIMULATIONS ELLIPTIC INSTABILITY ZIGZAG INSTABILITY TRAILING VORTICES PAIR BREAKUP DECAY RECONNECTION DYNAMICS |
| Issue Date | 14-Nov-2022 |
| Publisher | JOURNAL OF FLUID MECHANICS |
| Abstract | We conduct direct numerical simulations and study the evolution of a pair of counter-rotating vortices in a stratified and turbulent environment beyond the first vortex linking (which is due to the Crow instability). The initial position of the two vortices is perpendicular to the direction of thermal stratification. We vary the Froude number, the background turbulence intensity and the Reynolds number, covering strong, weak and neutral stratification; low, moderate and high background turbulence; and low and moderate Reynolds numbers. We observe a second vortex linking in a weakly stratified environment for the first time. The second vortex linking is followed by turbulence bursts that lead to the rapid decay of the residual vortices after the first vortex linking, leading to a short-living vortex pair. This challenges the conventional view that residual vortices have a long life span, which is true only in an unstratified environment. In addition to the second vortex linking, we observe the following. First, strong background turbulence quickly breaks the two vortices. Second, the two vortices induce secondary and tertiary vortices and lose energy to gravitational waves in a strongly stratified (Fr <= 0.7) environment. |
| URI | http://hdl.handle.net/20.500.11897/659097 |
| ISSN | 0022-1120 |
| DOI | 10.1017/jfm.2022.905 |
| Indexed | SCI(E) |
| Appears in Collections: | 工学院 湍流与复杂系统国家重点实验室 |
