What is Inviscid Flow?

Inviscid refers to a fluid or gas that does not experience any viscosity, or resistance to flow. In other words, an inviscid fluid flows smoothly and continuously without any internal friction or resistance. This is in contrast to viscous fluids, which do experience internal friction and exhibit more complex flow patterns.

Inviscid flow is typically observed in high-speed flows where the Reynolds number is very large, meaning that the inertial forces dominate over the viscous forces. In these conditions, the fluid is able to flow freely and without any significant loss of energy due to viscous effects. Examples of inviscid flows include airflow around an airfoil, water flowing down a river, and the flow of gas in a combustion engine.

Inviscid flow is often modeled using the Euler equations, which are a set of partial differential equations that describe the behavior of an inviscid fluid. These equations are simpler than the Navier-Stokes equations, which describe viscous flow, and are therefore more computationally efficient to solve. However, they do not account for the effects of viscosity, which can be important in many real-world applications.