SECONDARY FLOWS AND DEVELOPING, TURBULENT BOUNDARY-LAYERS IN A ROTATING DUCT

Citation
I. Macfarlane et al., SECONDARY FLOWS AND DEVELOPING, TURBULENT BOUNDARY-LAYERS IN A ROTATING DUCT, Journal of Fluid Mechanics, 373, 1998, pp. 1-32
Citations number
32
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanics,"Phsycs, Fluid & Plasmas
Journal title
ISSN journal
0022-1120
Volume
373
Year of publication
1998
Pages
1 - 32
Database
ISI
SICI code
0022-1120(1998)373:<1:SFADTB>2.0.ZU;2-X
Abstract
The work presented in this paper represents an experimental investigat ion into secondary flows, turbulent boundary layers and the interactio n of the two as they develop in a zero-pressure-gradient rotating flow field. A duct of intermediate aspect ratio was used to examine second ary flows and determine when they begin to govern the boundary layer d evelopment. The aspect ratio (A) was defined as duct height/width at t he upstream end of the working section. Measurements were taken at thr ee aspect ratios: A = 1, 2 and 4. A qualitative indication of secondar y flow strength was established with mean-cross-stream-plane velocity measurements. A first-order analysis of the secondary flow is presente d which provides a reasonable estimation of their strength. Mid-span m ean-flow, turbulence and spectra profiles were measured on the duct wa lls parallel to the axis of rotation. Results are generally presented for A = 2 and 1. For A = 4 and 2 there were minor effects of secondary flows observed on the mid-span mean flow parameters. The turbulent sh ear measurements showed some secondary flow effect for A = 2. All turb ulence and mean-flow quantities were strongly affected by secondary fl ows for A = 1. Spectra results presented for A = 2 showed most variati on at the low-to-mid wavenumber end. Spectra results for A = 1 showed a bodily shift of the whole spectrum towards low wavenumber on the pre ssure side and high wavenumber on the suction side.