Abstract
We demonstrate a reduction in the measured inner wall shear stress in moderately turbulent Taylor-Couette flows by depositing sprayable superhydrophobic microstructures on the inner rotor surface. The magnitude of reduction becomes progressively larger as the Reynolds number increases up to a value of 22% at . We show that the mean skin friction coefficient in the presence of the superhydrophobic coating can be fitted to a modified Prandtl–von Kármán–type relationship of the form from which we extract an effective slip length of . The dimensionless effective slip length , where is the viscous length scale, is the key parameter that governs the drag reduction and is shown to scale as in the limit of high Re.
- Received 1 September 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.014501
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