Publications [#353724] of Hongkai Zhao

Papers Published

1. Xu, J-J; Li, Z; Lowengrub, J; Zhao, H, Numerical Study of Surfactant-Laden Drop-Drop Interactions, Communications in Computational Physics, vol. 10 no. 2 (August, 2011), pp. 453-473, Global Science Press [doi]
   (last updated on 2024/04/24)

   Abstract:
   AbstractIn this paper, we numerically investigate the effects of surfactant on drop-drop interactions in a 2D shear flow using a coupled level-set and immersed interface approach proposed in (Xu et al., J. Comput. Phys., 212 (2006), 590-616). We find that surfactant plays a critical and nontrivial role in drop-drop interactions. In particular, we find that the minimum distance between the drops is a non-monotone function of the surfactant coverage and Capillary number. This non-monotonic behavior, which does not occur for clean drops, is found to be due to the presence of Marangoni forces along the drop interfaces. This suggests that there are non-monotonic conditions for coalescence of surfactant-laden drops, as observed in recent experiments of Leal and co-workers. Although our study is two-dimensional, we believe that drop-drop interactions in three-dimensional flows should be qualitatively similar as the Maragoni forces in the near contact region in 3D should have a similar effect.