In this work, we describe a simulation framework for fluid movement in a corrugated sawtooth channel whose walls are undergoing periodic repeated oscillations. The sawtooth geometry of the channel walls creates a fluid ratchet by generating an anisotropy in the fluid impedance. The simulations are developed using an immersed boundary method, and we present numerical results for both Newtonian and non-Newtonian fluids. These results are in agreement with physical studies of ratchets in the literature and with general flow behaviors expected for non-Newtonian fluids. In particular, we find enhanced mean flow rates for non-Newtonian fluids up to a critical value of the Weissenberg number. Existence of such a critical value has been shown for non-Newtonian flows in other environments, but has not been explored computationally for fluid ratchets. We also provide results which highlight the difference in movement of ratcheted non-Newtonian versus Newtonian fluids.

在这项工作中，我们描述了一个在波纹锯齿形通道中流体运动的模拟框架，该波纹形锯齿通道的壁正在经历周期性的反复振荡。通道壁的锯齿形几何形状通过在流体阻抗中产生各向异性来产生流体棘齿。使用沉浸边界方法进行了仿真，并且我们给出了牛顿流体和非牛顿流体的数值结果。这些结果与文献中对棘轮的物理研究以及非牛顿流体的一般流动特性相吻合。尤其是，我们发现非牛顿流体的平均流速得到提高，直至达到魏森伯格数的临界值。对于其他环境中的非牛顿流，已经显示了这样一个临界值的存在，但是对于流体棘轮，还没有进行过计算性的探索。