Drops, jets and bubbles

Drops, jets and bubbles occur in many different technological and scientifically relevant situations and, thus, have been the subject of a great deal of theoretical and experimental work. In the six lectures presented here, I have focused on the equilibria and dynamics of captive drops (or liquid bridges), the thermocapillary migration of drops. In the last lecture I give a brief introduction to the related problem of contact line motion and dynamic contact angles. (Contact line and angle behavior is an important aspect of captive, sessile and pendant drop dynamics.) In Chapter 1, the basic equations governing bridge dynamics and equilibria are introduced and a method for determining the stability of axisymmetric equilibrium shapes is outlined. Selected results for the stability of bridges subject to gravity and isorotation an discussed. In Chapter 2 we consider ID models of liquid bridge oscillation. These models are based on models used to describe axisymmetric jets and have been adapted for modeling liquid bridge dynamics. In Chapter 3, 2D and 3D liquid bridge oscillations are examined and the nonlinear behavior of bridges undergoing large amplitude oscillations is discussed. It is shown that, for nonlinear oscillations, liquid bridges behave like a soft spring. In Chapter 4 we consider different models of the breaking of jets, pendant drops and liquid bridges. In Chapter 5 we briefly analyze the Young-Goldstein-Block model of the thermocapillary migration of bubbles. In Chapter 6, we introduce and discuss recent experimental and theoretical work concerning dynamic contact angles and highlight the complexity of the behavior of moving contact lines.