Summary: ME 413 Systems Dynamics & Control Chapter 7: Fluid Systems and Thermal Systems
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A fluid system uses one or more fluids to achieve its purpose. Dampers and shock
absorbers are examples of fluid systems because they depend on the viscous nature of a fluid
to provide damping. In addition to providing damping, other applications of fluid systems
include actuators and processes that involve mixing, heating, and cooling of fluids.
Active vehicle suspensions use hydraulic and pneumatic actuators to provide forces
to supplement the passive spring and damping elements. Water supply, waste treatment, and
other chemical processing applications are examples of a general category of fluid systems
called "liquid-level-systems", because they involve regulating the volumes, and therefore the
levels of liquids in containers such as tanks.
A fluid might be either a liquid or a gas. A fluid is said to be incompressible if the fluid's
density remains constant despite changes in the fluid pressure. If the density changes with
pressure, the fluid is compressible.
7.2 MATHEMATICAL MODELING OF LIQUID LEVEL