In previous work, we have demonstrated the use of single-holed Armoured Microbubbles (AMBs) for microfluidic mixing and self-propulsion. AMBs are hollow partial spheres, inside which we capture a bubble. Under ultrasound, the bubble oscillates, generating a streaming flow with velocities of 1-100 mm/s in water. In this paper, inspired by our successful fabrication of a C60 geometry (buckyball), we study AMBs with multiple surface holes. We show more holes generate additional pairs of fast circulations around the AMB. However, as the number of holes increases further, the circulations become small and the in-plane flow is dominated by a source or sink flow. For an AMB with two different sized holes, we demonstrate each hole can be independently activated, potentially useful for multi-directional swimming.

中文翻译：

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多向气泡生成流

在之前的工作中，我们已经展示了使用单孔装甲微泡 (AMB) 进行微流体混合和自推进。AMB 是空心的部分球体，我们在其中捕获了一个气泡。在超声波下，气泡振荡，在水中产生速度为 1-100 毫米/秒的流动。在本文中，受我们成功制造 C60 几何体（巴基球）的启发，我们研究了具有多个表面孔的 AMB。我们展示了更多的孔会在 AMB 周围产生额外的快速循环对。然而，随着孔数的进一步增加，环流变小，面内流动以源流或汇流为主。对于具有两个不同大小孔的 AMB，我们证明每个孔都可以独立激活，这对于多向游泳可能有用。