{'fraction_non_alphanumeric': 0.01763046544428773, 'fraction_numerical': 0.0028208744710860366, 'mean_word_length': 5.757142857142857, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Letter: The effect of surface viscosity on the translational speed of droplets

This paper quantifies the effect of interfacial viscosity on the translational speed of a drop in Stokes flow. In the limit of negligible droplet deformation and surface concentration inhomogeneities, the droplet mobility is equal to a clean droplet with a modified interior viscosity ηin*=ηin+2ηκ3a, where ηκ is the interfacial dilational viscosity and a is the droplet radius. This paper focuses on the physical explanation of these results via symmetry/scaling arguments, which illustrates why interfacial shear viscosity is unimportant. We conclude by calculating how surface concentration inhomogeneities and two-body hydrodynamic interactions alter these results.This paper quantifies the effect of interfacial viscosity on the translational speed of a drop in Stokes flow. In the limit of negligible droplet deformation and surface concentration inhomogeneities, the droplet mobility is equal to a clean droplet with a modified interior viscosity ηin*=ηin+2ηκ3a, where ηκ is the interfacial dilational viscosity and a is the droplet radius. This paper focuses on the physical explanation of these results via symmetry/scaling arguments, which illustrates why interfacial shear viscosity is unimportant. We conclude by calculating how surface concentration inhomogeneities and two-body hydrodynamic interactions alter these results.