Abstract
In this experimental study, mass transfer characteristics in a turbulent channel flow of viscoelastic fluid was investigated by simultaneous particle image velocimetry and planar laser-induced fluorescence measurements. Instantaneous dye concentration field with fluctuating velocity vector showed spatial phase modulation in the streamwise velocity fluctuation and the dye concentration for the wall-normal velocity fluctuation. In addition, it was observed that hierarchically large-scale wavy motions with inclination transfer mass. A spatial spectral analysis allowed us to understand a higher wall-normal turbulent mass flux of low wave-number modes in the log-layer takes important role in comparison with the Reynolds shear stress. The existence of this characteristic wavy motion explains why the thinner dye concentration layer enhanced the magnitude of dye concentration fluctuation.
| Original language | English |
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| Publication status | Published - 2019 |
| Event | 11th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2019 - Southampton, United Kingdom Duration: 30 Jul 2019 → 2 Aug 2019 |
Conference
| Conference | 11th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2019 |
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| Country/Territory | United Kingdom |
| City | Southampton |
| Period | 30/07/19 → 2/08/19 |