This is an example of flow-driven, linear motion.
We will analyze an axial check valve to determine the valve opening distance for a supplied volume flow rate of water.
A spring provides resistance on the poppet, and keeps it closed while the flow rate is below a certain threshold.
As the flow rate is increased, the poppet opens by balancing the hydrodynamic forces with the resistive spring force.
We will define the initial position of the poppet, the limits of travel of the poppet, and the spring parameters. We will run with a relatively low flow rate which will partially open the poppet.