1. An analysis of superhydrophobic turbulent drag reduction mechanisms using direct numerical simulation
- Author
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Jonathan P. Rothstein, Michael B. Martell, and J. Blair Perot
- Subjects
Fluid Flow and Transfer Processes ,Physics ,Turbulence ,Mechanical Engineering ,Computational Mechanics ,Reynolds number ,Laminar sublayer ,Laminar flow ,Mechanics ,Slip (materials science) ,Condensed Matter Physics ,Physics::Fluid Dynamics ,symbols.namesake ,Classical mechanics ,Mechanics of Materials ,Drag ,Parasitic drag ,Shear stress ,symbols - Abstract
These surfaces have been shown to provide drag reduction in laminar and turbulent flows. In this work, direct numerical simulation is used to investigate the drag reducing performance of superhydrophobic surfaces in turbulent channel flow. Slip velocities, wall shear stresses, and Reynolds stresses are determined for a variety of superhydrophobic surface microfeature geometry configurations at friction Reynolds numbers of Re180, Re395, and Re590. This work provides evidence that superhydrophobic surfaces are capable of reducing drag in turbulent flow situations by manipulating the laminar sublayer. For the largest microfeature spacing, an average slip velocity over 80% of the bulk velocity is obtained, and the wall shear stress reduction is found to be greater than 50%. The simulation results suggest that the mean velocity profile near the superhydrophobic wall continues to scale with the wall shear stress and the log layer is still present, but both are offset by a slip velocity that is primarily dependent on the microfeature spacing. © 2010 American Institute of Physics. doi:10.1063/1.3432514
- Published
- 2010
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