In this study, the dynamic analysis of Pipeline Inspection Gauge (PIG) flow control in
natural gas and liquid pipeline is considered. The basic equations are differential forms
of the mass and linear momentum for compressible liquid and gas flows. The fluid flow
equations and a linear momentum equation of the PIG are solved simultaneously using an
appropriate numerical method. Solution of these nonlinear equations results in a set of
diagrams for the variations of the fluid pressure, mass flow rate of the gas and the PIG
velocity through the pipeline. Comparing the results of mathematical model for the PIG
with the established experimental data in a segment of Ahwaz gas pipeline shows a good
agreement between the measurements and computations.