# PRES

A simple perfect gas monitored volume where the relative pressure is a function of relative volume or a function of time.

In the PRES monitored volume, the relative pressure is defined as
`P`_{rel} = pressure inside of
monitored volume - atmospheric pressure.

The relative pressure is defined using a function in one of two ways. By default, the relative pressure is defined as a function of the relative volume ${P}_{rel}\left(\frac{{V}_{0}}{V}\right)$ , or the pressure can be a function of time ${P}_{rel}\left(t\right)$ .