[TommyM]

Hi All,

I am simulating the air flow in a simple straight pipe with adiabatic walls.

The conditions are as follows:

• Incompressible steady flow
• Inlet temperature = 450 C deg
• Inlet velocity = 100 m/s
• Outlet pressure = 1 atm

The problem should be very easy. Anyway, looking at the results, I see a high temperature gradient close to the wall surfaces, in direction normal to the wall (passing from 450 C of the core flow to 458 C at the wall prism layer).

First, I am a little rusty about this topic but, is it correct to have a thermal boundary layer in a problem like this with adiabatic walls?
I would say "yes" because total temperature should remains constant, thus a decrease of velocity at the wall implies an increase of temperature. Anyway, I am keen to listen others' opinion.

Second, if it is correct to have it, is such a high temperature change (Delta T = 8 C deg) a reasonable value for this problem?

Thanks.

Tommy