论文标题
在高péclet数字上向自由悬浮的颗粒转移
Mass transfer to freely suspended particles at high Péclet number
论文作者
论文摘要
在理论分析中，我们概括了众所周知的渐近结果，以获得从悬浮在大péclet数字上的开放式途径流中的任意刚性粒子表面的传递速率的表达式，$ \ textrm {pe} $。流动可能会稳定或周期性。我们将此结果应用于数值评估表面通量的表达式，以在由稳定的线性剪切驱动的Stokes流中自由悬浮的轴对称椭球（球体）。我们通过在$ \ textrm {pe} = 10^1-10^4 $的范围内进行的数值模拟进行补充，并确认在大péclet编号上的良好协议。我们的结果使我们能够检查颗粒形状对一系列流量的粒子对表面通量的影响。当背景流是无关的时，表面通量是稳定的，仅由三个参数规定：péclet数，粒子纵横比和应变拓扑。我们观察到，与具有等效表面积的扁面球体相比，细长的斜体球体往往会经历更高的表面通量。对于旋转流，颗粒可能开始旋转或滚动，这可能会抑制或增强由于粒子相对于应变场的重新调整而引起的对流转移。
In a theoretical analysis, we generalise well known asymptotic results to obtain expressions for the rate of transfer of material from the surface of an arbitrary, rigid particle suspended in an open pathline flow at large Péclet number, $\textrm{Pe}$. The flow may be steady or periodic in time. We apply this result to numerically evaluate expressions for the surface flux to a freely suspended, axisymmetric ellipsoid (spheroid) in Stokes flow driven by a steady linear shear. We complement these analytical predictions with numerical simulations conducted over a range of $\textrm{Pe} = 10^1 - 10^4$ and confirm good agreement at large Péclet number. Our results allow us to examine the influence of particle shape upon the surface flux for a broad class of flows. When the background flow is irrotational, the surface flux is steady and is prescribed by three parameters only: the Péclet number, the particle aspect ratio and the strain topology. We observe that slender prolate spheroids tend to experience a higher surface flux compared to oblate spheroids with equivalent surface area. For rotational flows, particles may begin to spin or tumble, which may suppress or augment the convective transfer due to a realignment of the particle with respect to the strain field.
