I ran a flow simulation in SW16 of a pipe system where I applied increasing flow rates at the inlet and recorded the resulting pressure value occurring on the inlet face to determine system pressure drop. There is a pressure opening boundary condition at the outlet of environmental pressure. To verify these results I performed physical testing on the pipe system with a pressure gauge placed at the same point as the inlet boundary condition in my model. However the results recorded in testing do not match the results obtained using SW flow simulation. I have attached the solid works file with this post as well as a image below with the pressure values. Can anyone spot any areas within my simulation that could be leading to the variation in pressure values when compared to the tested results? Any suggestions would be greatly appreciated. I have attached images of the study below.