When a fluid is in motion, it must move in such a way that mass is conserved. To see how mass conservation places restrictions on the velocity field, consider the steady flow of fluid through a duct ...

Abstract: A continuity equation for the occupation factor of the energy states is proposed and used to demonstrate the existence of a negative diffusion capacitance in tunnel diodes.

Model solving the 2D shallow water equations. The momentum equations are linearized while the continuity equation is solved non-linearly. The model was developed as part of the "Bornö Summer School in ...