eprintid: 4598
rev_number: 6
eprint_status: archive
userid: 425
dir: disk0/00/00/45/98
datestamp: 2021-08-11 01:44:07
lastmod: 2021-08-11 01:44:07
status_changed: 2021-08-11 01:44:07
type: article
metadata_visibility: show
creators_name: Van Luc, Nguyen
creators_name: Toai Tuyn, Phan
creators_name: Viet Dung, Duong
creators_name: Nam Tuan Phuong, Le
creators_id: duongdv@vnu.edu.vn
title: Turbulent energy cascade associated with viscous reconnection of two vortex rings
ispublished: pub
subjects: Aerospace
subjects: isi
divisions: sae
abstract: Collision of two vortex rings (VR) initially arranged in axis-offset and orthogonal configurations at Reynolds numbers (ReΓ ) in a range 5000−200 000 was simulated to investigate turbulent energy cascade associated with their reconnection. Two elliptical VRs are generated by joining each part of the first VR with another part of the second VR for the axis-offset collision. While two VRs associate to form a double U-shaped vortex, and this vortex reconnects itself at two points to form three elliptical VRs linked by the vortex filaments for the orthogonal collision. Many vortex structures in various scales and shapes, including small-scale VRs and horseshoe vortices, are observed in connection regions for both cases. As ReΓ increasing, the energy of formed small vortices raises and their wavenumber (k) range enlarges. The flow energy spectrum approaches a k−5/3 slope of the Kolmogorov hypotheses at low wavenumbers. For the axis-offset collision, the energy spectrum at medium wavenumbers continuously changes from k−3.0 at ReΓ = 5000 to k−1.8 at ReΓ =200 000, and the exponent (α) of the wavenumber is determined by a function as α = 0.3304ln(ReΓ ) − 5.6538. Meanwhile, the energy spectrum at two medium-wavenumber subranges for the orthogonal collision with ReΓ ≥ 20 000 approaches slopes of k−3.0 and k−2.6. Turbulent mixing performance due to the axis-offset collision of two vortex rings is better than that with the orthogonal one.
date: 2021-08
date_type: published
publisher: AIP
id_number: DOI: 10.1063/5.0058317
full_text_status: none
publication: Physics of Fluids
volume: 33
refereed: TRUE
issn: 1070-6631
citation:   Van Luc, Nguyen and Toai Tuyn, Phan and Viet Dung, Duong and Nam Tuan Phuong, Le  (2021) Turbulent energy cascade associated with viscous reconnection of two vortex rings.  Physics of Fluids, 33 .    ISSN 1070-6631