Figure 1

(a),(b) Schematic views of the microfluidic devices with open and side traps. (c) Magnitude of the vertical component of cell velocity overlaid on a phase contrast image of the trap at time 210 min of the run shown in movie S1; (d) Space-time plot of the cells’ exit velocity component averaged over the lower $20\mu \mathrm{m}$ of the trap in (c).Reuse & Permissions

Figure 2

Results of the continuum hydrodynamic model in the overdamped limit using $c(z)=A+(z/L_z{)}^2$, $L_z=1$, $\alpha =1$. (a) Three regimes of narrow-channel flows: symmetric (1), asymmetric (2), and periodic (3) flows; (b) Bifurcation diagram of the narrow-channel flows in the ($A$, $\gamma$) plane. Symbol $S$ denotes symmetric flow, $A$, asymmetric, and $O$, oscillatory flow regimes, double symbols ($A/S$, $O/S$) indicate domains of bistability according to local bifurcation analysis. Points 1,2,3 correspond to time series shown in (a). (c) Streaming instability domain in the parameter plane ($A$, $\gamma$) for different values of viscosity coefficient $\mu$. Streaming for a given $\mu$ occurs for $A$ below the corresponding curve; (d) Velocity field for the eigenfunction near the onset of a streaming instability, with wave vector $k=2$, $\gamma =1$, $A=0.045$, $\mu =0.001$. Since the flow is inverted for $\pi /4\le x\le 3\pi /4$, only half the $x$ period is displayed.Reuse & Permissions

Figure 3

Streaming patterns in a wide side trap: (a) A snapshot of a cell population from a typical DES simulation of short rods (${\ell }_{\mathrm{div}}=3$) at time $t=30$ of the simulation shown in panel (b). Cells are colored according to their values of $f$. Panels (b) and (c) show ($x$, $t$) diagrams of the $z$ component of cell velocity averaged over the $z$ axis. Both simulations had the same parameters and were initiated at $t=-15$) with a single cell, but for the simulation but in (b) $f$ was allowed to evolve freely from the very beginning while in (c) $f$ was fixed at $c(z)/2$ until time $t=5$ and then relaxed. (d) Snapshot of the population of longer rods (${\ell }_{\mathrm{div}}=5$). Parameters are $L_x=150$, $L_z=20$, $\alpha =0.5$, $\gamma =0.5$, $c(z)=1+200(z/L_z{)}^4$.Reuse & Permissions