Abstract
We introduce boundary adapted wavelets, which are orthogonal and have the same scale in the three spatial directions. The construction thus yields a multiresolution analysis. We analyse direct numerical simulation data of turbulent channel flow computed at a friction Reynolds number of 395, and investigate the role of coherent vorticity. Thresholding of the vorticity wavelet coefficients allows us to split the flow into two parts, coherent and incoherent flows. The coherent vorticity is reconstructed from its few intense wavelet coefficients and the coherent velocity is reconstructed using Biot–Savart's law. The statistics of the coherent flow, i.e. energy and enstrophy spectra, are close to the statistics of the total flow, and moreover, the nonlinear energy budgets of the total flow are very well preserved. The remaining incoherent part, represented by the large majority of the weak wavelet coefficients, corresponds to a structureless, i.e. noise-like, background flow whose energy is equidistributed.
| Original language | English |
|---|---|
| Pages (from-to) | 352-372 |
| Number of pages | 21 |
| Journal | Journal of Turbulence |
| Volume | 18 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 3 2017 |
| Externally published | Yes |
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Keywords
- coherent structure
- direct numerical simulation
- Turbulent channel flow
- wavelet
ASJC Scopus subject areas
- Computational Mechanics
- Condensed Matter Physics
- Mechanics of Materials
- Physics and Astronomy(all)
Cite this
Coherent structure extraction in turbulent channel flow using boundary adapted wavelets. / Sakurai, Teluo; Yoshimatsu, Katsunori; Schneider, Kai; Farge, Marie; Morishita, Koji; Ishihara, Takashi.
In: Journal of Turbulence, Vol. 18, No. 4, 03.04.2017, p. 352-372.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Coherent structure extraction in turbulent channel flow using boundary adapted wavelets
AU - Sakurai, Teluo
AU - Yoshimatsu, Katsunori
AU - Schneider, Kai
AU - Farge, Marie
AU - Morishita, Koji
AU - Ishihara, Takashi
PY - 2017/4/3
Y1 - 2017/4/3
N2 - We introduce boundary adapted wavelets, which are orthogonal and have the same scale in the three spatial directions. The construction thus yields a multiresolution analysis. We analyse direct numerical simulation data of turbulent channel flow computed at a friction Reynolds number of 395, and investigate the role of coherent vorticity. Thresholding of the vorticity wavelet coefficients allows us to split the flow into two parts, coherent and incoherent flows. The coherent vorticity is reconstructed from its few intense wavelet coefficients and the coherent velocity is reconstructed using Biot–Savart's law. The statistics of the coherent flow, i.e. energy and enstrophy spectra, are close to the statistics of the total flow, and moreover, the nonlinear energy budgets of the total flow are very well preserved. The remaining incoherent part, represented by the large majority of the weak wavelet coefficients, corresponds to a structureless, i.e. noise-like, background flow whose energy is equidistributed.
AB - We introduce boundary adapted wavelets, which are orthogonal and have the same scale in the three spatial directions. The construction thus yields a multiresolution analysis. We analyse direct numerical simulation data of turbulent channel flow computed at a friction Reynolds number of 395, and investigate the role of coherent vorticity. Thresholding of the vorticity wavelet coefficients allows us to split the flow into two parts, coherent and incoherent flows. The coherent vorticity is reconstructed from its few intense wavelet coefficients and the coherent velocity is reconstructed using Biot–Savart's law. The statistics of the coherent flow, i.e. energy and enstrophy spectra, are close to the statistics of the total flow, and moreover, the nonlinear energy budgets of the total flow are very well preserved. The remaining incoherent part, represented by the large majority of the weak wavelet coefficients, corresponds to a structureless, i.e. noise-like, background flow whose energy is equidistributed.
KW - coherent structure
KW - direct numerical simulation
KW - Turbulent channel flow
KW - wavelet
UR - http://www.scopus.com/inward/record.url?scp=85011710577&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85011710577&partnerID=8YFLogxK
U2 - 10.1080/14685248.2017.1284326
DO - 10.1080/14685248.2017.1284326
M3 - Article
VL - 18
SP - 352
EP - 372
JO - Journal of Turbulence
JF - Journal of Turbulence
SN - 1468-5248
IS - 4
ER -