Hydraulic Systems
Model the change in height of the water in three tanks, with the third tank leaking.
The pressures at the bottoms of the tanks 1, 2, and 3 are represented as , , and , respectively. The pipe from tank 1 branches off to tanks 2 and 3. The pressure at the pipe branch is given as . Flow rates depend on pressure differences and geometry:
All the fluid leaving tank 1 should enter tank 2 and tank 3. This is represented as a constraint. Also, the height of the fluid in the tank is related to the pressure in the tank by Toricelli's law:
The rate at which the fluid leaves or enters the tank (i.e. flow rate) is directly proportional to the rate of change of the height of the fluid in the tank. This relation comes through mass conservation of incompressible fluids: