The steady flow test rig is a device for in-cylinder swirl and tumble flows velocity measurement and the analysis of the flow performance of cylinder head (intake and exhaust ports), manifold and carburetor in internal combustion engines. The test rigs can also to maintain quality control on parts for various gas turbine components. In this study we have investigated the effect of pressure on in-cylinder swirl flow velocity in the steady flow test rig which is equipped swirl meter with experimental and numerical simulation methods. The repeatability of experiments and the uncertainty analysis are performed to ensure the quality of the measurements. Three dimensional numerical simulations are applied by using the finite volume method by the ANSYS Fluent software. The flow around the swirl meter is simulated by moving reference frame method. The simulation results show good agreement with experimental results and also due to limitations of operating conditions of the rig this simulation approach can compensate the limitations of operating conditions of test rig. In this work it is showed that correlation between given rotational speed to the swirl meter and torque applied on it, is a linear function of rotational speed. The study also showed that by increasing the pressure, in-cylinder swirl flow velocity increase and created correlation between swirl flow velocity and pressure difference can be approximated by an exponential function.