Particle Tracing of Unsteady Flow in Chambers
Connected by Valves and a Piston

This animation shows unsteady flow in chambers connected by valves and a piston. The left chamber has an inlet and the right chamber has an outlet. As the piston moves down, the left valve opens, the right valve closes, and gas is sucked through the inlet into the left chamber and the piston. As the piston moves up, the left valve closes, the right valve opens and gas is pushed through the open valve into the right chamber and the outlet.

Particles are injected at a fixed rate from the inlet. The particle motions clearly show the path of the gas through the chambers, valves and piston.