Li Yunyun, Yin Qingqing, Marchesoni Fabio, Debnath Tanwi, Ghosh Pulak K
Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
Dipartimento di Fisica, Università di Camerino, I-62032 Camerino, Italy.
Phys Rev E. 2021 Mar;103(3):L030106. doi: 10.1103/PhysRevE.103.L030106.
We numerically investigated the transport of a passive colloidal particle in a one-dimensional periodic array of planar counter-rotating convection rolls at high Péclet numbers. We show that advection-enhanced diffusion is drastically suppressed by an external transverse bias but strongly reinforced by a longitudinal drive of appropriate intensity. Both effects are magnified by imposing free-slip flows at the array's edges. The dependence of the diffusion constant on an external forcing is interpreted as a measure of the fluid-mechanical robustness of the flow boundary layer mechanism governing diffusion in convection rolls.
我们通过数值方法研究了在高佩克莱数下，一维平面反向旋转对流涡旋周期性阵列中被动胶体粒子的输运情况。我们表明，外部横向偏置会大幅抑制平流增强扩散，但适当强度的纵向驱动会强烈增强平流增强扩散。通过在阵列边缘施加自由滑移流，这两种效应都会被放大。扩散常数对外部强迫的依赖性被解释为对流涡旋中控制扩散的流动边界层机制的流体力学稳健性的一种度量。
