Direct Measurement of the Flow Field around Swimming Microorganisms
Direct Measurement of the Flow Field around Swimming Microorganisms
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DOI：
10.1103/physrevlett.105.168101
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发表时间：
2010-10-11
影响因子：
8.6
通讯作者：
Tuval, Idan
中科院分区：
文献类型：
--
作者：
Drescher, Knut;Goldstein, Raymond E.;Tuval, Idan
游动的微生物产生流动，影响它们的相互作用并改变它们悬浮液的流变学。虽然在理论上进行了广泛的研究，但这些流动尚未在任何自由游泳的微生物周围进行详细测量。我们报告这样的测量的微型植物团藻carteri和衣藻reinhardtii。微小的（类似于0.3%）的密度过剩的V.卡特里超过水导致一个强有力的主导Stokeslet的贡献，与广泛假设的应力波流只有一个修正的subleading源偶极子项。这意味着卡特弧菌的悬浮液具有与沉降颗粒的悬浮液相似的特征。在C. reinhardtii，其中显着的流体动力学相互作用很可能发生定性不同的拉应力，并可以描述一个简单的三斯托克斯模型。
Swimming microorganisms create flows that influence their mutual interactions and modify the rheology of their suspensions. While extensively studied theoretically, these flows have not been measured in detail around any freely-swimming microorganism. We report such measurements for the microphytes Volvox carteri and Chlamydomonas reinhardtii. The minute (similar to 0.3%) density excess of V. carteri over water leads to a strongly dominant Stokeslet contribution, with the widely-assumed stresslet flow only a correction to the subleading source dipole term. This implies that suspensions of V. carteri have features similar to suspensions of sedimenting particles. The flow in the region around C. reinhardtii where significant hydrodynamic interaction is likely to occur differs qualitatively from a puller stresslet, and can be described by a simple three-Stokeslet model.