👉 The excluded fluid, also known as the viscous dissipation or internal friction fluid, is a theoretical construct in fluid dynamics that represents an idealized medium through which viscous forces act within a fluid. This concept arises when considering the internal friction and energy dissipation within a fluid due to its viscosity. In practical scenarios, this "fluid" is not a physical substance but rather a mathematical construct used to model and analyze the effects of viscosity on fluid flow. It helps in understanding how energy is lost within a flowing fluid due to the internal resistance caused by molecular interactions, which is crucial for accurate predictions in various applications, such as aerodynamics, hydrodynamics, and heat transfer.
