TY - JOUR
T1 - Large Eddy Simulation of a Vortex Ring Impacting a Bump
AU - Ren , Heng
AU - Zhao , Ning
AU - Lu , Xi-Yun
JO - Advances in Applied Mathematics and Mechanics
VL - 3
SP - 261
EP - 280
PY - 2014
DA - 2014/06
SN - 6
DO - http://doi.org/10.4208/aamm.2013.m285
UR - https://global-sci.org/intro/article_detail/aamm/18.html
KW - Large eddy simulation, vortex ring, vortical structure, turbulent state.
AB - <p style="text-align: justify;">A vortex ring impacting a three-dimensional bump is studied
using large eddy simulation for a Reynolds number Re=$4$x$10^4$ based on the initial diameter and
translational speed of the vortex ring. The effects of bump
height and vortex core thickness for thin and thick vortex
rings on the vortical flow phenomena and the underlying
physical mechanisms are investigated. Based on the analysis of
the evolution of vortical structures, two typical kinds of
vortical structures, i.e., the wrapping vortices and the
hair-pin vortices, are identified and play an important role in
the flow state evolution. The boundary vorticity flux is
analyzed to reveal the mechanism of the vorticity generation on
the bump surface. The circulation of the primary vortex ring
reasonably elucidates some typical phases of flow evolution.
Further, the analysis of turbulent kinetic energy reveals the
transition from laminar to turbulent state. The results
obtained in this study provide physical insight into the
understanding of the mechanisms relevant to the flow evolution
and the flow transition to turbulent state.</p>