Growing bubbles and freezing drops: depletion effects and tip singularities

In this thesis, the author investigates the growth of gas bubbles in a supersaturated solution and the freezing of water drops when placed on a cold plate. Supersaturated solutions are common in nature and industry; perhaps the best know examples are carbonated drinks, such as beer or soda. These are bottled under pressure, and contain an amount of dissolved gas, which is in a saturated state. When opened, the pressure in the container decreases to the same level as atmospheric pressure. At that moment the solution is supersaturated, which means it contains more gas that what it would thermodynamically “want to”. Hence, the gas needs to escape from the liquid, and given the right conditions bubbles will form in this process, as we usually see them on the walls of our glass or bottle when having a drink. Besides this example, bubbles can grow for similar reasons in the blood of scuba divers with decompression sickens, volcanic magma, molten polymers and metals, and oil wells. Hence, understanding the basic physics of how bubbles grow can contribute to better understand (and perhaps control) some of these phenomena. The experimental study presented here focuses on bubbles that grow under a supersaturation ten times smaller than a normal carbonated drink, which is especially interesting for oil extraction processes. The freezing drop problem holds an analogy to the bubble growth in that both phenomena are driven by mass diffusion and heat conduction, respectively, which are physically analogous. Understanding the physics of solidification processes is crucial for 3D printing and other deposition processes. It is also a very important aspect in the preparation of ice before curling matches. In this case, the investigation focussed on the formation of the pointy tip that appears at the end of the freezing process. In this work it is experimentally and theoretically shown that for a wide temperature range the shape of this tip does not depend on the freezing dynamics.