Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session M39: Pipe Flow
8:00 AM–9:57 AM,
Tuesday, November 20, 2018
Georgia World Congress Center Room: Ballroom 3/4
Chair: Xiaohua Wu, Royal Military College of Canada
Abstract ID: BAPS.2018.DFD.M39.4
Abstract: M39.00004 : Large-scale motions in turbulent minimal pipe flows at Reτ ≈ 930, 2000 and 3000*
8:39 AM–8:52 AM
Hyung Jin Sung
Direct numerical simulations of turbulent minimal pipe flow at Reτ ≈ 930, 2000 and 3000 are performed to elucidate spanwise behavior of large scales. The streamwise domain is set to Lx+ ≈ 1000, which corresponds to the characteristic streamwise length of near-wall streaks. The large scales of streamwise velocity fluctuations (u) are enhanced due to the periodic boundary condition with short streamwise length. In the premultiplied spanwise energy spectra of u, two outer peaks appear at λz/R = 0.6 and 1.3 with the increase in their magnitudes compared to those observed in a long streamwise domain (Lx = 30R). The conditional two-point correlations of the large scales (λz < 0.8R) in the outer region show that the large scales penetrate close to the wall with increasing Reτ. At Reτ ≈ 3000, the conditional correlations of the very large scales (λz > 0.8R) coincide with each other regardless of the reference wall-normal location, indicating the spatial confinement of very large scales. This behavior enhances the energy at the large scales, which ultimately leads to the presence of the two outer peaks in the spanwise energy spectra.
*This study was supported by the National Research Foundation of Korea (no. 2018- 001483), and partially supported by the Supercomputing Center (KISTI).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DFD.M39.4
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