Fig. 2

a Results from numerical simulation show that the body force (red arrows) generated by leaky SAWs can induce a vortex streaming pattern within the IDT area. The body force is applied to the liquid above the IDT which is highlighted by the white dashed box. The color of the channel indicates the amplitude of the body force. b Numerical and c experimental demonstration of acoustic streaming in the zebrafish rotation area on the xy-planes close to the channel top and bottom, respectively. The yellow shaded box indicates the IDT area. The experimentally measured streaming pattern (c) represented by the trajectories of 1-μm diameter fluorescent particles, as visualized in a composite of stacked images, matches with the numerically calculated streaming pattern (b) driven by acoustic leaky waves generated by the IDTs. d Image sequence showing a cycle of the rotational motion of a 5 dpf anesthetized zebrafish larva in the acoustofluidic device. The larva was stably rotated counterclockwise with respect to the yz-plane by the fluid-induced drag force. Scale bar: 1 mm. e The rotation periods of four typical 5 dpf zebrafish larvae (length: 3.43–3.6 mm, width: 0.63–0.71 mm) as a function of the driving voltage (Vpp). The rotational periods vary among larvae since each larva has unique characteristics for body shape, size, and density distribution. Overall, the rotational speed of the zebrafish larvae increases as the driving voltage increases. Data are graphed as the mean ± SD (n = 6). Scale bar: 1 mm. f The rotation angle over a single rotational cycle with respect to time for four typical zebrafish larvae at 12.75 Vpp. Source data is available as a source data file.