Is the Zero Reynolds Number Approximation Valid for Ciliary Flows?
Is the Zero Reynolds Number Approximation Valid for Ciliary Flows?
复制标题
零雷诺数近似对于纤毛流是否有效？
作者：
Da Wei;Parviz G. Dehnavi;Marie‐Eve Aubin‐Tam;D. Tam
微米级纤毛周围的流体动力流动通常用Stokes方程来模拟。实验研究了零雷诺数近似的有效性，提出了一种基于光钳的流动速度测量方法，该方法可以测量高空间和时间分辨率的周期性流动。我们发现，节拍的纤毛产生了一种流动，这与斯托克斯方程预测的斯托克斯莱特场有根本的不同。特别是，流速在空间上以更快的速度衰减，并随着与纤毛距离的增加而逐渐延迟。这表明，非定常纤毛流的拟定常近似和Stokes方程的使用并不总是合理的，涡度扩散的有限时间尺度是不能忽略的。我们的结果对微泳运动员的同步性和集体动力学的研究具有重要意义。
Stokes equations are commonly used to model the hydrodynamic flow around cilia on the micron scale. The validity of the zero Reynolds number approximation is investigated experimentally with a flow velocimetry approach based on optical tweezers, which allows the measurement of periodic flows with high spatial and temporal resolution. We find that beating cilia generate a flow, which fundamentally differs from the stokeslet field predicted by Stokes equations. In particular, the flow velocity spatially decays at a faster rate and is gradually phase delayed at increasing distances from the cilia. This indicates that the quasisteady approximation and use of Stokes equations for unsteady ciliary flow are not always justified and the finite timescale for vorticity diffusion cannot be neglected. Our results have significant implications in studies of synchronization and collective dynamics of microswimmers.
影响因子：
8.6
作者：
Drescher, Knut;Goldstein, Raymond E.;Tuval, Idan
通讯作者：
Tuval, Idan