Affiliations: Department of Mechanical Engineering, Kagoshima
University, 1-21-40, Korimoto, Kagoshima 890-0065, Japan. e-mail:
li@mech.kagoshima-u.ac.jp | Turbulent Mixing and Unsteady Aerodynamics Laboratory,
A22, Research Complex Engineering, Michigan State University, East Lansing,
Michigan 48824, USA. | Institute of Industrial Science, The University of
Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Abstract: The two-dimensional orthogonal wavelet transform was applied to the
LIF image of lobed mixing jet for identifying the multi-scale turbulent
structures. The digital imaging slice photographs at z /D = 1.0 and 1.5 with Re
= 3000 were respectively decomposed into seven image components with different
broad scales. These image components provided the visualized information on the
multi-scale structures in a lobed mixing turbulent jet. The cores and edges of
the vortices and the coherent structures at different resolutions or scales can
be easily extracted. It was found that the scale range of the coherent
structure becomes narrow along the downstream direction. The size of the
intermediate- and small-scale structures does not vary significantly with
downstream distance.
