Static temperature in thermodynamics and fluid mechanics, is the actual temperature of a fluid (such as air or gas) as it exists at a point, independent of its bulk motion of the fluid. It represents the internal energy of the fluid associated with random molecular motion and is the temperature that would be measured by a thermometer moving with the fluid (that is, with no relative velocity between the sensor and the flow). The concept becomes particularly important when comparing it to total (or stagnation) temperature. While static temperature accounts only for internal molecular energy, total temperature includes both that internal energy and the kinetic energy of the fluid’s bulk motion. When a high-speed fluid is forced to come to a complete stop isentropically (without losing energy), its kinetic energy is converted into internal energy, causing the temperature to rise.
