Multi-point velocity measurements have been performed in turbulent pipe flow at ReD = 1.5×105 and combined with cross-spectral and proper orthogonal decomposition analysis to elucidate information on the structure of the large- and very-large-scale motions in the outer layer of wall-bounded flows. The results indicate that in the outer layer the large-scale motions (LSM) may be composed of detached eddies with a wide range of azimuthal scales, whereas in the logarithmic layer they are attached. The very-large-scale motions (VLSM) have large radial scales, are concentrated around a single azimuthal mode and make a smaller angle with the wall compared to the LSM. The results support a hypothesis that only the detached LSM in the outer layer align to form the VLSM.
|Number of pages||18|
|Journal||Journal of Fluid Mechanics|
|State||Published - May 25 2010|
Bibliographical noteFunding Information:
The support of the Office of Naval Research under grants N00014-07-1-0111 and N00014-09-1-0263 (programme manager Ron Joslin) is gratefully acknowledged.
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering