TITLE:
Effects of Orbital Motion on the Velocity Field of Boundary Layer Flow over a Rotating Disk
AUTHORS:
Mizue Munekata, Takaomi Utatsu, Hiroyuki Yoshikawa, Yasuhiro Okumura
KEYWORDS:
Boundary Layer Flow, Rotating Disk, Transition, Vortices, Hot-Wire Anemometer
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.7 No.2,
May
18,
2017
ABSTRACT: The purpose of this study is to investigate experimentally the effects of orbital motion on the velocity field of boundary layer flow over a rotating disk. The characteristics of velocity field at a fixed orbital angular section measured by a hot-wire anemometer show that the structure of the 3-dimensional boundary layer flow is deformed elliptically and displaced in a certain direction that is not in the orbital radial direction, but the direction of deformation depends on the combination of orbital and rotational directions. For coincide orbital and rotational directions, there are regions where the intensity of low-frequency disturbances increases rapidly in a certain central region (laminar region under pure rotation). The transient vortices, which form streaks on the coating film, are considered to be destroyed by low-frequency disturbances. However, for opposite orbital and rotational directions, the low-frequency disturbances are not observed in any section. As the adding orbital speed increases, the intensity of velocity fluctuations in the turbulence region becomes larger in the expected except in a certain region. This location of the region also depends on the direction of deformation or the combination of orbital and rotational directions.