Direct numerical simulations of turbulent flows over superhydrophobic surfaces
Direct numerical simulations of turbulent flows over superhydrophobic surfaces
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DOI：
10.1017/s0022112008004916
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发表时间：
2009-02-10
影响因子：
3.7
通讯作者：
Rothstein, Jonathan P.
中科院分区：
文献类型：
--
作者：
Martell, Michael B.;Perot, J. Blair;Rothstein, Jonathan P.
采用直接数值模拟方法研究了超疏水表面在槽道湍流中的减阻性能。SHS将联合收割机表面粗糙度与疏水性结合，并且在某些情况下可以支持无剪切的空气-水界面。滑移速度，壁面剪切应力和雷诺应力被认为是各种SHS微特征的几何构型在摩擦雷诺数Re-τ近似为180。对于最大的微特征间距研究，平均滑移速度超过75%的体积速度，壁面剪应力减少被发现是近40%。模拟结果表明，超疏水壁附近的平均速度分布继续与壁面剪切应力成比例，但被抵消的滑移速度，随着微特征间距的增加而增加。
Direct numerical simulations (DNSs) are used to investigate the drag-reducing performance of superhydrophobic surfaces (SHSs) in turbulent channel flow. SHSs combine surface roughness with hydrophobicity and can, in some cases, support a shear-free air-water interface. Slip velocities, wall shear stresses and Reynolds stresses arc considered for a variety of SHS microfeature geometry configurations at a friction Reynolds number of Re-tau approximate to 180. For the largest microfeature spacing Studied, an average slip velocity over 75% of the bulk velocity is obtained, and the wall shear stress reduction is found to be nearly 40%. The Simulation results suggest that the mean velocity profile near the superhydrophobic wall continues to scale with the wall shear stress but is offset by a slip velocity that increases with increasing microfeature spacing.