SYSTEM MODEL
The system is basically a first-order system. The tank acts as a fluid capacitor where fluid enters and leaves the tank. According to mass balance,
where Qin is the flow rate of water into the tank, Q the rate of water storage in the tank, and Qout the flow rate of water out of the tank. If A is the cross-sectional area of the tank, and h the height of water inside the tank, (11.1) can be written as
