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FLUENT uses gauge pressure internally in order to minimize round-off errors stemming from small differences of big numbers. Any time an absolute pressure is needed, it is generated by adding the so-called "operating pressure" to the gauge pressure:
  absolute pressure = gauge pressure + "operating pressure"

. This "operating pressure" is also used in the "incompressible ideal gas" model as mentioned above. We will specify the "operating pressure" as equal to the measured ambient pressure since the absolute pressure in the pipe varies only slightly from this (you do get significant variations in gauge pressures though).

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Change the Type to  axis and click OK. FLUENT will set the flow gradients at this boundary in accordance with the axisymmetric assumption.

Now let's set up the heated wall section.

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https://confluence.cornell.edu/download/attachments/111221574/heated%20wall.png

 
As discussed in the powerpoint presentation, we need to set:

• velocity and temperature (plus k and epsilon for the turbulence model equations) at the inlet
• pressure at the outlet

For incompressible flow, the flow adjusts to the pressure at the outlet (consider this as a signal you are sending the flow about what it needs to do inside the pipe).

Select: Now let's set the inlet boundary condition.
Boundary Conditions > inlet
Note that the boundary Type is automatically set to velocity-inlet. FLUENT has an automatic mechanism to set the pick a boundary condition type according to the name you give and settings that you have selected previously (this could be dangerous if FLUENT selects the wrong boundary type and a lackadaisical user doesn't change it.). In this case, it gets it right.

Click . So let's click Edit... to set up the correct inlet parameters. A The Velocity Inlet window pop outpops up. Enter 25.05 next to Velocity Magnitude (m/s). For Turbulent Kinetic Energy (m2/s2), enter value 0.09. For Turbulent Dissipation Rate (m2/s3), enter value 16. Note that k and epsilon are not measured and are rough guess values. Click OK to close the window.The results should not be sensitive to these inputs since most of the turbulence is generated in the boundary layers (ideally, you should check the sensitivity of your calculation to this setting). 

https://confluence.cornell.edu/download/attachments/111221574/velocity%20inlet_sm.png

 
Now  Now click on Thermal tab and enter 298.15K for Temperature. Click OK to close the window.
 
Finally, set up the outlet boundary condition.:
Boundary Conditions > Outlet
Again, proper FLUENT selects the pressure-outlet boundary Type is settype and its guess turns out to be right. 

Click Edit... to set up appropriate pressure outlet conditionto specify the gauge pressure at the outlet. Enter -1112.3 for Gauge Pressure (From experiment, measured outlet pressure is 97225.9 Pa. Corresponding gauge pressure = 97225.9 Pa - reference operating pressure = -1112.3 Pa)

https://confluence.cornell.edu/download/attachments/111221574/outlet%20pressure.png

 
We are done setting up the boundary conditions Now FLUENT knows all necessary elements of our beloved BVP (domain, governing equations and boundary conditions). In the Solution step, we'll prod the beast to obtain an approximate numerical solution to our BVP.

Go to Step 5: Solution

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