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A small piece of rapidly melting solid argon shows two concurrent phase changes. The transition from solid to liquid, and gas to liquid (shown by the white condensed water vapour). Other phase changes include: Transition to a mesophase between solid and liquid, such as one of the "liquid crystal" phases.
The classical Stefan problem aims to describe the evolution of the boundary between two phases of a material undergoing a phase change, for example the melting of a solid, such as ice to water. This is accomplished by solving heat equations in both regions, subject to given boundary and initial conditions. At the interface between the phases ...
Different modes of two-phase flows. In fluid mechanics, two-phase flow is a flow of gas and liquid — a particular example of multiphase flow.Two-phase flow can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating, separated flows, and dispersed two-phase flows where one phase is present in the form of particles, droplets, or bubbles in ...
Triple points mark conditions at which three different phases can coexist. For example, the water phase diagram has a triple point corresponding to the single temperature and pressure at which solid, liquid, and gaseous water can coexist in a stable equilibrium (273.16 K and a partial vapor pressure of 611.657 Pa).
Within each phase, the properties are uniform but between the two phases properties differ. Water in a closed jar with an air space over it forms a two-phase system. Most of the water is in the liquid phase, where it is held by the mutual attraction of water molecules.
Pepper is sprinkled onto the surface of the water in the left dish; when a droplet of soap is added to that water, the specks of pepper move rapidly outwards. The Marangoni effect (also called the Gibbs–Marangoni effect) is the mass transfer along an interface between two phases due to a gradient of the surface tension.
The discontinuity in , and other properties, e.g. internal energy, , and entropy,, of the substance, is called a first order phase transition. [12] [13] In order to specify the unique experimentally observed pressure, (), at which it occurs another thermodynamic condition is required, for from Fig.1 it could clearly occur for any pressure in the range .
For the shown case, a bichromatic group of gravity waves on the surface of deep water, the group velocity is half the phase velocity. In this example, there are 5 + 3 / 4 waves between two wave group nodes in space, while there are 11 + 1 / 2 waves between two wave group nodes in time.