UDF to control Static Pressure (in cylinder)

James

Hello, I am trying to perform a simulation of the compressible flow down the exit pipe of a cylinder. I have taken readings of static pressure in the cylinder and I want to use them as boundary conditions for the pipe inlet. However when using pressure inlet boundary condition it only allows me to specify total pressure and supersonic initial guage pressure. I have written a udf for the static pressure profile at the inlet but when I use that for the total pressure, the static pressure on the inlet is calculated by fluent and is different. How do I control the static pressure on the inlet to match my actual readings? Thanks in advance for your help. James