Turbulent fluctuations above the buffer layer of wall-bounded flows

By Javier Jiménez, Sergio Hoyas. Journal of Fluid Mechanics, 2008

261 citations recorded by the source corpus.

The behaviour of the velocity and pressure fluctuations in the logarithmic and outer layers of turbulent flows is analysed using spectral information and probability density functions from channel simulations at Reτ≤2000. Comparisons are made with experimental data at higher Reynolds numbers. It is found, in agreement with previous investigations, that the intensity profiles of the streamwise and spanwise velocity components have logarithmic ranges that are traced to the widening spectral range of scales as the wall is approached. The same is true for the pressure, both theoretically and observationally, but not for the normal velocity or for the tangential stress cospectrum, although even those two quantities have structures with lengths of the order of several hundred times the wall distance. Because the logarithmic range grows longer as the Reynolds number increases, variables which are ‘attached’ in this sense scale in the buffer layer in mixed units. These results give strong support to the attached-eddy scenario proposed by Townsend (1976), but they are not linked to any particular eddy model. The scaling of the outer modes is also examined. The intensity of the streamwise velocity at fixed y/h increases with the Reynolds number. This is traced to the large-scale modes, and to an increased intensity of the ejections but not of the sweeps. Several differences are found between the outer structures of different flows. The outer modes of the spanwise and wall-normal velocities in boundary layers are stronger than in internal flows, and their streamwise velocities penetrate closer to the wall. As a consequence, their logarithmic layers are thinner, and some of their logarithmic slopes are different. The channel statistics are available electronically at http://torroja.dmt.upm.es/ftp/channels/.

Subfields: Computational Mechanics, Environmental Engineering, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/a07c40ef997b1435d3aaba75cdc9ee66d33b3848

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Citations in the corpus

Coherent structures in wall-bounded turbulence (2017, result): “Both predictions have been confirmed observationally: by numerical simulations in the case of u3 (Jiménez & Hoyas 2008), and experimentally in the case of u1 (Marusic et al. 2013).”
Velocity statistics in turbulent channel flow up to $Re_{\tau }=4000$ (2014, background): “In this case, the formation of an extended logarithmic layer is much clearer, and we find evidence for a universal scaling w′2/u2τ ≈ B3 − A3 log(y/h), (3.8) with A3≈ 0.44, B3≈ 0.95, first found by Jiménez & Hoyas (2008) at lower Reτ (with A3 ≈ 0.5, B3 ≈ 0.8).”
Turbulence in supersonic boundary layers at moderate Reynolds number (2011, methodology): “One should also note the presence of a bump in the distribution of w′ in the outer layer, which is probably the signature of large-scale dynamics in the outer-layer bulges, and which is not present in channel flow DNS (Jiménez & Hoyas 2008).”
On the logarithmic region in wall turbulence (2013, result): “Tentative support has also come from other studies, notably Jiménez & Hoyas (2008).”
Statistical structure of self-sustaining attached eddies in turbulent channel flow (2015, background): “…turbulence intensity with the Reynolds number (Marusic & Kunkel 2003), and the logarithmic wall-normal dependence on the secondand higher-order statistical moments of the wall-parallel velocity components (Perry & Chong 1982; Jiménez & Hoyas 2008; Marusic et al. 2013; Meneveau & Marusic 2013).”
High–Reynolds Number Wall Turbulence (2011, methodology): “Recent surveys of the available data by Jiménez & Hoyas (2008) and Buschmann et al. (2009), together with analysis of DNS data by del Álamo & Jiménez (2003), del Álamo et al. (2004), and Hoyas & Jiménez (2006), provide support for the Townsend attached-eddy hypothesis predictions for v and w,…”
Turbulent boundary layers and channels at moderate Reynolds numbers (2010, methodology): “It was noted by Jiménez & Hoyas (2008) that there were at the time essentially no experiments or simulations in which the very long streamwise scales of the u component were clearly resolved, although the available evidence suggested λx 25δ.”
Estimation of turbulent convection velocities and corrections to Taylor's approximation (2009, methodology): “Using those data, Jiménez & Hoyas (2008) noted that the outer energy peak in experimental boundary layers extends closer to the wall than in numerical channels, although they cautioned that this could be due in part to the difference between wavenumber and frequency spectra.”
Aspect ratio effects in turbulent duct flows studied through direct numerical simulation (2014, background): “(c) and (d): The mean statistics at z = 0 and z = 2.75hin terms of y+ are shown as follows: ( ) 1 · U+ , ( ) 2 · u2+, ( ) 12 · w2+, ( ) −16 · uv+. Channel flow data by Hoyas and Jiménez [41] at nominally same Reynolds number is also shown in (a) and (c) with dashed lines for comparison.”