Before revision: , the Navier–Stokes equation simplifies to the Stokes equation, which by neglecting the bulk term is: where is the viscosity, is the velocity in the direction, is the gravity component in the direction and is the pressure.
After revision: , the Navier–Stokes equation simplifies to the Stokes equation, which by neglecting the bulk term is: where is the viscosity, is the velocity in the direction, and is the pressure.