TY - JOUR
T1 - Effect of bubbles on turbulent kinetic energy transport in downward flow measured by time-resolved PTV
AU - Lelouvetel, Julie
AU - Nakagawa, Masashi
AU - Sato, Yohei
AU - Hishida, Koichi
N1 - Funding Information:
The authors acknowledge the financial support provided by the Japanese Society for Promotion of Science (No. 20:08810). We also thank Dr. T. Tanaka for his helpful comments.
PY - 2011/4
Y1 - 2011/4
N2 - A time-resolved particle tracking velocimetry (PTV) system and a shape projection imaging system were used to investigate the turbulence modifications by bubbles in a downward bubbly flow. Two bubble sizes and three mean void fractions were tested at a Reynolds number of about 20,000. The strong modifications in the mean velocity, turbulent kinetic energy (TKE) budget, and velocity spectra are observed in the central region of the pipe that has a high local void fraction. In particular, kinetic energy production decreased, whereas the TKE dissipation rate increased. This suggests that the transfer of energy due to bubbles has a very large effect on the TKE budget. Moreover, velocity spectra reveal that the presence of bubbles modifies the length scales of turbulent eddies, which contain, transfer, and dissipate energy.
AB - A time-resolved particle tracking velocimetry (PTV) system and a shape projection imaging system were used to investigate the turbulence modifications by bubbles in a downward bubbly flow. Two bubble sizes and three mean void fractions were tested at a Reynolds number of about 20,000. The strong modifications in the mean velocity, turbulent kinetic energy (TKE) budget, and velocity spectra are observed in the central region of the pipe that has a high local void fraction. In particular, kinetic energy production decreased, whereas the TKE dissipation rate increased. This suggests that the transfer of energy due to bubbles has a very large effect on the TKE budget. Moreover, velocity spectra reveal that the presence of bubbles modifies the length scales of turbulent eddies, which contain, transfer, and dissipate energy.
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U2 - 10.1007/s00348-010-0906-0
DO - 10.1007/s00348-010-0906-0
M3 - Article
AN - SCOPUS:79954430373
SN - 0723-4864
VL - 50
SP - 813
EP - 823
JO - Experiments in Fluids
JF - Experiments in Fluids
IS - 4
ER -