When immersed in solution, surface-active particles interact with solute molecules and migrate along gradients of solute concentration. Depending on the conditions, this phenomenon could arise from either diffusiophoresis or the Marangoni effect, both of which involve strong interactions between the fluid and the particle surface. We introduce here a numerical approach that can accurately capture these interactions, and thus provide an efficient tool to understand and characterize the phoresis of soft particles. The model is based on a combination of the extended finite element—that enable the consideration of various discontinuities across the particle surface—and the particle-based moving interface method—that is used to measure and update the interface deformation in time. In addition to validating the approach with analytical solutions, the model is used to study the motion of deformable vesicles in solutions with spatial variations in both solute concentration and temperature.

中文翻译：

---

软囊泡和液滴的泳动运动：基于 XFEM/粒子的数值解

当浸入溶液中时，表面活性粒子与溶质分子相互作用并沿溶质浓度梯度迁移。根据条件的不同，这种现象可能由扩散泳或 Marangoni 效应引起，两者都涉及流体和颗粒表面之间的强相互作用。我们在此介绍一种可以准确捕获这些相互作用的数值方法，从而提供一种有效的工具来理解和表征软粒子的泳动。该模型基于扩展有限元（能够考虑粒子表面的各种不连续性）和基于粒子的移动界面方法（用于及时测量和更新界面变形）的组合。除了使用分析解决方案验证该方法之外，