1. Bubbly Turbulent Drag Reduction Is a Boundary Layer Effect
- Author
-
Dennis P. M. van Gils, Detlef Lohse, Th.H. van den Berg, Daniel P. Lathrop, Faculty of Science and Technology, and Physics of Fluids
- Subjects
Physics::Fluid Dynamics ,Physics ,Drag coefficient ,Boundary layer ,Flow separation ,Classical mechanics ,Drag ,Parasitic drag ,Wave drag ,Aerodynamic drag ,Drag divergence Mach number ,General Physics and Astronomy ,Mechanics - Abstract
In turbulent Taylor-Couette flow, the injection of bubbles reduces the overall drag. On the other hand, rough walls enhance the overall drag. In this work, we inject bubbles into turbulent Taylor-Couette flow with rough walls (with a Reynolds number up to 4 x 10(5), finding an enhancement of the dimensionless drag as compared to the case without bubbles. The dimensional drag is unchanged. As in the rough-wall case no smooth boundary layers can develop, the results demonstrate that bubbly drag reduction is a pure boundary layer effect.
- Published
- 2007