Nguyen Quoc T, Papavassiliou Dimitrios V
School of Chemical, Biological and Materials Engineering, The University of Oklahoma, 100 East Boyd Street, SEC T-301, Norman, Oklahoma 73019, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Dec;88(6):063015. doi: 10.1103/PhysRevE.88.063015. Epub 2013 Dec 23.
In this study, plane Poiseuille-Couette flow is simulated as a model for specified streamwise slip on one of the channel walls. The relative velocity between the two walls is set to be 1, 2, and 4 in viscous wall units. This is equivalent to the presence of a superhydrophobic surface at one of the channel walls that causes fluid to slip on the boundary. The results show that the streamwise slip forces turbulence in the near-wall region to tend towards a limiting one-component state. This leads to the suppression of small scale turbulence and laminarization close to the wall and then to drag reduction. The selective weakening of the streamwise vorticity close the wall and the observed decrease of turbulence kinetic energy production can then be considered as a consequence of this effect. Changes in the coherent structures, including a decrease of sweep events and increase of ejection events close to the wall where slip occurs, are also observed.
在本研究中，平面泊肃叶 - 库埃特流被模拟为通道壁之一上指定流向滑移的模型。两壁之间的相对速度在粘性壁单位中设置为1、2和4。这相当于在通道壁之一处存在超疏水表面，导致流体在边界上发生滑移。结果表明，流向滑移使近壁区域的湍流趋向于极限单分量状态。这导致近壁处小尺度湍流的抑制和层流化，进而实现减阻。靠近壁面的流向涡度的选择性减弱以及观测到的湍动能产生的减少可被视为这种效应的结果。还观察到了相干结构的变化，包括靠近发生滑移的壁面处扫掠事件的减少和喷射事件的增加。
