Affiliations: Department of Mechanical and System Engineering, Kyoto
Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan. | Graduate school, Kyoto Institute of Technology
(present address: Yanmar Diesel Engine Co. Ltd., 7-35 Sanwa-cho, Nagahama-city,
Shiga pref., 526-0055, Japan). | Graduate school, Kyoto Institute of Technology,
Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Abstract: Three-dimensional particle tracking velocimetry (3-D PTV)
measurements with a two-camera system have been conducted for a turbulent water
plane Couette flow with an oil droplet in order to understand the modification
of shear-dominant turbulence by the droplet. The parameters of the
stereogrammetry, which are crucial for calculating the spatial coordinate of
tracer particles from 2-D images of two cameras, have been determined with a
careful calibration. The experimental results show that the axial and
wall-normal turbulence intensities and the turbulent kinetic energy are
enhanced locally in the confluence regions where axial main flow over the
interface meets the secondary flow along the interface in the wall-normal
direction. The secondary flows were observed only around the equator of the
droplet. The wall-normal and transverse turbulence intensities are found to
increase in the region above the droplet. This is due to the change in the
direction of the primary flow over the top of the droplet. The turbulence in
the other region is attenuated mainly because of the attenuation of the
generation and evolution of the coherent structure in the neighbourhood of the
droplet.
