Eddy self-similarity in turbulent pipe flow
Author(s) | Hellström, L. H. O. | |
Author(s) | Van Buren, T. | |
Author(s) | Vaccaro, J. C. | |
Author(s) | Smits, A. J. | |
Date Accessioned | 2024-06-24T18:42:57Z | |
Date Available | 2024-06-24T18:42:57Z | |
Publication Date | 2024-05-15 | |
Description | This article was originally published in Physical Review Fluids. The version of record is available at: https://doi.org/10.1103/PhysRevFluids.9.054607. ©2024 American Physical Society. | |
Abstract | For wall-bounded turbulent flows, Townsend's attached eddy hypothesis proposes that the logarithmic layer is populated by a set of energetic and geometrically self-similar eddies. These eddies scale with a single length scale, their distance to the wall, while their velocity scale remains constant across all self-similar structures. To investigate the existence of such structures in fully developed turbulent pipe flow, stereoscopic particle image velocimetry measurements were performed in two parallel cross-sectional planes, spaced apart by a varying distance from 0 to 9.97𝑅, where 𝑅 is the radius of the pipe, for friction Reynolds numbers Re𝜏=1310, 2430, and 3810. The instantaneous turbulence structures are sorted by width using an azimuthal Fourier decomposition and then azimuthally aligned to create a set of average eddy velocity profiles. The profiles exhibit geometric self-similar behavior in the azimuthal plane for eddies with spanwise length scales (𝜆𝜃/𝑅) spanning from 1.03 to 0.175. The streamwise similarity is then investigated using two-point correlations, where the structures exhibit a self-similar behavior with length scales (𝜆𝜃/𝑅) ranging from approximately 0.88 to 0.203. The candidate structures thereby establish full three-dimensional geometric self-similarity. In addition, the characteristic velocity magnitudes exhibit self-similarity within these ranges, using a velocity scale that is proportional to eddy size. This unexpected result is reconciled with the attached eddy hypothesis in terms of sampling probabilities. | |
Sponsor | This work was supported under ONR Grants No. N00014-15-1-2402 and No. N00014-17-1-2309. | |
Citation | Hellström, L. H. O., T. Van Buren, J. C. Vaccaro, and A. J. Smits. “Eddy Self-Similarity in Turbulent Pipe Flow.” Physical Review Fluids 9, no. 5 (May 15, 2024): 054607. https://doi.org/10.1103/PhysRevFluids.9.054607. | |
ISSN | 2469-990X | |
URL | https://udspace.udel.edu/handle/19716/34516 | |
Language | en_US | |
Publisher | Physical Review Fluids | |
Title | Eddy self-similarity in turbulent pipe flow | |
Type | Article |
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