Department of Mathematics, Faculty of Science Engineering and Technology, Swinburne University of Technology Hawthorn, Victoria, 3122, Australia.
Soft Matter. 2019 Mar 6;15(10):2284-2291. doi: 10.1039/c8sm02102c.
Marangoni flow created by the gradient of surface tension can be used to transport small objects along fluid interfaces. We study lateral motion of a fully wetted self-propelled body (swimmer) at a fluid-fluid interface. The swimmer releases a surfactant at a constant rate inducing a surface tension gradient. The dynamics of the insoluble surfactant is incorporated by taking into account advection by the Marangoni flow, surface diffusion and homogeneous decomposition reaction. We show that the translational speed of a Marangoni swimmer is increased as compared with the self-propulsion speed of a chemically inactive surface-bound swimmer. Flow induced in-plane rotation of the swimmer with an elongated body is generally weak so that its trajectory in the steady state is a straight line. A non-motile thin rod that releases surfactant at one of its ends is capable of surfing on the self-generated surfactant cloud. Steady surfing occurs along the body length with the source of the surfactant at the back end acting as a propulsion engine.
由表面张力梯度产生的马兰戈尼流可用于沿流体界面运输小物体。我们研究了完全润湿的自推进体（游泳者）在流体界面上的横向运动。游泳者以恒定速率释放表面活性剂，从而产生表面张力梯度。通过考虑由马兰戈尼流引起的平流、表面扩散和均相分解反应，将不可溶表面活性剂的动力学纳入其中。我们表明，与化学上不活跃的表面结合的游泳者的自推进速度相比，马兰戈尼游泳者的平移速度增加了。具有细长体的游泳者的平面内旋转诱导流通常较弱，因此其在稳态下的轨迹是一条直线。在一端释放表面活性剂的无动力薄杆能够在自生成的表面活性剂云中冲浪。稳定的冲浪发生在沿体长方向，表面活性剂的源位于后端，充当推进引擎。
