Abstract
The objective of this study is to experimentally investigate the structure of the boundary layer flow over a rotating disk under orbital motion in order to reveal the generation mechanism and characteristics of disturbances. The disk diameter is 300 mm, and the orbital radius is one third of the disk radius (50mm). The velocity field in the boundary layer flow at high Reynolds number is measured by a hot-wire anemometer (as for the measurement height z = 0.65mm from the disk surface), at a fixed orbital angler portion. The structure of the three-dimensional boundary layer flow is deformed elliptically and flown away to a certain direction which is not orbital radial direction, by orbital motion. The effects on the turbulent region, the fluctuating intensity becomes larger except a certain region, as the orbital speed increases. There are observed independently of the direction of rotation. However the flown direction and the location of expecting region depend on the direction of rotation. In the coinciding orbital and rotational directions, the low frequency disturbances which have high intensity of fluctuating velocity are observed in the upstream region of transition point. The transient vortices which form streaks on the coating film are considered to be destroyed by the low frequency disturbances. However, in the opposite orbital and rotational directions, the low frequency disturbances are not observed at any section.
Published Version
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