What is navier stokes equation?

The Navier-Stokes equations are a set of nonlinear partial differential equations that describe the motion of fluid substances, such as liquids and gases. They account for various forces acting on the fluid, including viscosity, pressure, and external forces, and are fundamental in fluid dynamics. These equations are used to model a wide range of phenomena, from weather patterns to the flow of air over wings. Solving the Navier-Stokes equations in three dimensions remains one of the major unsolved problems in mathematics.