000228650 001__ 228650
000228650 005__ 20180913064347.0
000228650 0247_ $$2doi$$a10.1039/c6sm01636g
000228650 022__ $$a1744-683X
000228650 02470 $$2ISI$$a000400876600011
000228650 037__ $$aARTICLE
000228650 245__ $$aSwimming with a cage: low-Reynolds-number locomotion inside a droplet
000228650 260__ $$aCambridge$$bRoyal Society of Chemistry$$c2017
000228650 269__ $$a2017
000228650 300__ $$a13
000228650 336__ $$aJournal Articles
000228650 500__ $$aSY. Reigh and L. Zhu contributed equally to this work.
000228650 520__ $$aInspired by recent experiments using synthetic microswimmers to manipulate droplets, we investigate the low-Reynolds-number locomotion of a model swimmer (a spherical squirmer) encapsulated inside a droplet of a comparable size in another viscous fluid. Meditated solely by hydrodynamic interactions, the encaged swimmer is seen to be able to propel the droplet, and in some situations both remain in a stable co-swimming state. The problem is tackled using both an exact analytical theory and a numerical implementation based on a boundary element method, with a particular focus on the kinematics of the co-moving swimmer and the droplet in a concentric configuration, and we obtain excellent quantitative agreement between the two. The droplet always moves slower than a swimmer which uses purely tangential surface actuation but when it uses a particular combination of tangential and normal actuations, the squirmer and droplet are able to attain the same velocity and stay concentric for all times. We next employ numerical simulations to examine the stability of their concentric co-movement, and highlight several stability scenarios depending on the particular gait adopted by the swimmer. Furthermore, we show that the droplet reverses the nature of the far-field flow induced by the swimmer: a droplet cage turns a pusher swimmer into a puller, and vice versa. Our work sheds light on the potential development of droplets as self-contained carriers of both chemical content and self-propelled devices for controllable and precise drug deliveries.
000228650 6531_ $$aLow-Reynolds-number locomotion
000228650 6531_ $$asquirming
000228650 6531_ $$ahydrodynamic interaction
000228650 6531_ $$adroplet-based cell encapsulation
000228650 6531_ $$aboundary element method
000228650 700__ $$aReigh, Shang Yik$$uUniv Cambridge, Dept Appl Math & Theoret Phys, Ctr Math Sci, Wilberforce Rd, Cambridge CB3 0WA, England
000228650 700__ $$0248190$$aZhu, Lailai$$g245903$$uEcole Polytech Fed Lausanne, Lab Fluid Mech & Instabil, CH-1015 Lausanne, Switzerland
000228650 700__ $$0244721$$aGallaire, Francois$$g189938$$uEcole Polytech Fed Lausanne, Lab Fluid Mech & Instabil, CH-1015 Lausanne, Switzerland
000228650 700__ $$aLauga, Eric$$uUniv Cambridge, Dept Appl Math & Theoret Phys, Ctr Math Sci, Wilberforce Rd, Cambridge CB3 0WA, England
000228650 773__ $$j13$$k17$$q3161-3173$$tSoft Matter
000228650 8564_ $$s18298470$$uhttps://infoscience.epfl.ch/record/228650/files/swimmer_in_droplet_SM17.pdf$$yPublisher's version$$zPublisher's version
000228650 909C0 $$0252358$$pLFMI$$xU12052
000228650 909CO $$ooai:infoscience.tind.io:228650$$pSTI$$particle
000228650 917Z8 $$x245903
000228650 937__ $$aEPFL-ARTICLE-228650
000228650 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000228650 980__ $$aARTICLE