Damping of liquid sloshing by foams: from everyday observations to liquid transport

We perform experiments on the sloshing dynamics of liquids in a rectangular container submitted to an impulse. We show that when foam is placed on top of the liquid the oscillations of the free interface are significantly damped. The ability to reduce sloshing and associated splashing could find applications in numerous industrial processes involving liquid transport. When a container is set in motion, the free surface of the liquid starts to slosh, i.e. oscillate. For a frequency of motion corresponding to the resonant frequency of the surface wave, the amplitude of the waves can increase significantly and if the amplitude of sloshing is large enough splashing and/or drop formation are possible [1, 2]. The sloshing dynamics lead to challenging technical constraints in various applications. For example, sloshing leads to considerable pressure forces on the walls of the containers used for transport of oil and liquefied gas [3]. Therefore, the characterization of the amplitude of the generated waves and the investigation of methods to damp sloshing such as solid foams [4] or baffles [5] are important. Such effects are also observed when a glass of water is handled carelessly and the fluid sloshes or even spills over the rims of the container [6]. It is a common observation that beer does not slosh as readily as water, which suggests that the presence of foam could be used to damp sloshing, as illustrated in Figure 1. In this communication, we consider the effect on sloshing of a liquid foam placed on top of liquid in a rectangular cell. We present here experimental visualizations of the motion of the free interface and its time evolution. ∗[email protected] †[email protected]