Hello Dear,

"Report" is not for determining input pressure.

You can set this in "Solution Initialization">Patch.

If you work with incompressible fluids, there is no need to specify the pressure. The gradient matters, but absolute values do not. If you work with compressible fluids, you can set the pressure under boundary conditions --> operating pressure. This sets a reference pressure at a user-specified location in your domain, and computes pressure in the rest of the field on this basis. The option to set both pressure and velocity on your entire inlet is not available (and doing so would likely lead to issues), but you can set your reference pressure, for example, at a point of your inlet boundary.

Wassef Ahmed Agila hopefully this will help you . jazakallah

thank you Mr Keivan Nateghi

but sir i didn't want to calculate the inlet pressure< am just wondering while my checking for the out let pressure and velocity i coincidently i checked the inlet ones and pressure was incorrect as the one i input. why? this is the question.

Assalamualikum Sajid Ahammed thank you for replying and jazakallah khiran, sir, yes the fluid is water (incompressible), but how don't we need to specify the in let pressure for this type of flow?. we are mainly doing this simulation to study the effect of pressure on that pipe and the problem I faced is: when I set the inlet velocity and pressure as 10m/s & 7Mpa , constantly I found the pressure is incorrect when I was extracting them from the results as it shows on the photo.

Dear Wassef Ahmed Agila

"Supersonic/Initial Gauge Pressure" sets the static pressure on the boundary when the flow becomes (locally) supersonic and in other cases like your case it is ignored.

see the fluent help link:

https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node1124.htm#:~:text=Supersonic%2FInitial%20Gauge%20Pressure%20sets,initial%20values%20(see%20Section%2026.9.

When your inlet boundary condition is set to velocity-inlet, the "Supersonic/Initial Gauge Pressure" option does not work and if you change the magnitude of this option e.g. from 7000000 to 0 or another magnitude, the results will be the same, because your model is not supersonic. In your simulation, the velocity magnitude (10 m/s) just made your pressure magnitude on the inlet boundary and you can see it in the fluent report as the static or dynamic pressure.

Other pressure reports are defined as follow:

Static pressure + Dynamic Pressure = Total Pressure

Static Pressure + Operating Pressure (Defined in Operating condition menu) = Absolute Pressure

So, your pressure result (inlet total pressure = 132895.13) is made of Static pressure + Dynamic Pressure.

XAV expert

https://fluidcodes.ir/pressure/

Amir Sabernaeemi thank you dear