and
Kiyoshi Yamamoto**
*Department of Mechanical Engineering and Control
systems, University of Electro-Communications,
**National Aerospace Laboratory
abstract
We investigate the interaction of a Lamb-Oseen vortex and external turbulence
by direct numerical simulations. Initial external turbulence ( Rλ≒
120) is produced by another numerical simulation based on the
Fourier-spectral method. According to flow visualization, fine structures
(worms) are stretched by the differential rotation of the columnar vortex, and
spiral-like filament structures are formed around the columnar vortex. The
columnar vortex is deformed by the vortex wave excited by the interaction
between the columnar vortex and ambient turbulence. The flow field is analyzed
statistically, and the energy transfer between the inside and the outside of
the core of the columnar vortex is studied in detail.
| Received 17 May 2002, accepted 17 September 2002 |
Naoya Takahashi