The turbulent rotating-disk boundary layer

Authors: Imayama, S.I., Lingwood, R. J., Alfredsson, P.H.
Document Type: Article
Pubstate: Published
Journal: Eur. J. Mech. B/Fluids
Volume: 48   245-253
Year: 2014


The turbulent boundary layer on a rotating disk in otherwise quiescent fluid is discussed. The aim of this study is to give a statistical description of the azimuthal velocity to compare it with a turbulent two-dimensional flat-plate boundary layer. Determining the wall friction velocity accurately is particularly challenging and here this is done through direct measurement of the velocity distribution close to the rotating disk in the very thin viscous sublayer by the use of hot-wire anemometry. Compared with other flow cases, has the advantage of the highest relative velocity being at the wall itself (if the hot-wire probe is in the laboratory frame of reference), thereby limiting the effect of heat conduction to the wall from the hot-wire probe. Experimental results of mean, rms, skewness and flatness as well as spectral information are provided and compared with results obtained for a two-dimensional boundary layer. It is shown that turbulence statistics are similar in the inner region, although the maximum spectral content is found at smaller wavelengths for the rotating case. This indicates that the outer flow structures are less influential in the inner region for the rotating case.