Marangoni effect

About: Marangoni effect is a research topic. Over the lifetime, 5336 publications have been published within this topic receiving 98562 citations. The topic is also known as: Gibbs–Marangoni effect.

Bubble velocities: further developments on the jump discontinuity

Abstract: The motion of a gas bubble in a non-Newtonian fluid has been further examined in order to determine the conditions for the possible existence of a discontinuity in the bubble velocity-bubble volume log–log plot. It has been proposed in the past that this phenomenon was the result of a sudden change in the hydrodynamics of the moving bubble, resulting in a transition from a Stroke to a Hadamard regime. Furthermore, this abrupt transition was only qualitatively attributed to the elasticity of the fluid. Using our data as well as those of Leal et al., we demonstrate here that the discontinuity results as a balance between elastic and Marangoni instabilities, providing another major difference between Newtonian and non-Newtonian hydrodynamics.

The effect of surfactant on bursting gas bubbles

Abstract: A numerical technique, based on the boundary integral method, is developed to allow the modelling of unsteady free-surface flows at large Reynolds numbers in cases where the surface is contaminated by some surface-active compound. This requires the method to take account of the tangential stress condition at the interface and is achieved through a boundary-layer analysis. The constitutive relation that forms the surface stress condition is assumed to be of the Boussinesq type and allows the incorporation of surface shear and dilatational viscous forces as well as Marangoni effects due to gradients in surface tension. Sorption kinetics can be included in the model, allowing calculations for both soluble and insolube surfactants. Application of the numerical model to the problem of bursting gas bubbles at a free surface shows the greatest effect to be due to surface dilatational viscosity which drastically reduces the amount of surface compression and can slow and even prevent the information of a liquid jet. Surface tension gradients give dilatational elasticity to the surface and thus also significantly prevent surface compression. Surface shear viscosity has a smaller effect on the interface motion but results in initially increased surface concentrations due to the sweeping up of surface particles ahead of the inward-moving surface wave.

Free Liquid Surface Response Induced by Fluctuations of Thermal Marangoni Convection

Abstract: The original enthusiasm for processing in a microgravity environment has been slightly dimmed by the fact that liquid bridges are susceptible to surface oscillations and Marangoni convection. It has now been found that time fluctuations in the temperature gradient induce free liquid surface oscillations, which lead to large amplitudes in the vicinity of the resonances and possibly to the disintegration of the liquid system. An analytical solution leading to the magnification functions and phases of velocity, pressure distribution, and surface elevation is presented for an arbitrary axially periodic temperature field. Nomenclature a = radius of liquid column f(z) = function of angular coordinate z (/' = d//dz) /o, 77 = modified Bessel function of zeroth and first order and first kind, respectively p = liquid pressure r,