Drag reduction in bubbly Taylor-Couette turbulence.


In Taylor-Couette flow the total energy dissipation rate and therefore the drag can be determined by measuring the torque on the system. We do so for Reynolds numbers between Re=7 x 10(4) and Re=10(6) after having injected (i) small bubbles (R=1 mm) up to a volume concentration of alpha=5% and (ii) buoyant particles (rhop/rhol=0.14) of comparable volume concentration. In case (i) we observe a crossover from little drag reduction at smaller Re to strong drag reduction up to 20% at Re=10(6). In case (ii) we observe at most little drag reduction throughout. Several theoretical models for bubbly drag reduction are discussed in view of our findings.

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@article{Berg2005DragRI, title={Drag reduction in bubbly Taylor-Couette turbulence.}, author={Thomas H van den Berg and Stefan Luther and Daniel P. Lathrop and Detlef Lohse}, journal={Physical review letters}, year={2005}, volume={94 4}, pages={044501} }