The Continuity Equation is an important part of understanding how fluids move in different industries. It is based on the idea that mass is conserved, which means that the amount of fluid doesn’t change as it flows through a system.

For fluids that don’t change in density, this equation tells us that the mass flow rate has to stay the same along a path called a streamline. This means that if we consider a fluid's density (which we can call ρ), its speed (which we can call v), and the area it flows