👉 An "under fluid" refers to a type of fluid that exists below the surface of another fluid or solid, often filling gaps or spaces within a larger container. This can include gases dissolved in liquids (dissolved gases), gases trapped within solids (such as air bubbles in ice or water), or liquids flowing beneath other layers. For example, carbon dioxide dissolving in water forms an under fluid layer, creating a distinct boundary between the dissolved gas and pure water. This phenomenon plays a crucial role in various natural processes, like oceanic carbon sequestration and the formation of bubbles in boiling liquids.
