
Streamwiseperiodic flow with heat transfer from constanttemperature walls is one of two classes of periodic heat transfer that can be modeled by FLUENT. A periodic fullydeveloped temperature field can also be obtained when heat flux conditions are specified. In such cases, the temperature change between periodic boundaries becomes constant and can be related to the net heat addition from the boundaries as described in this section.

Periodic heat transfer can be modeled only if you are using the pressurebased solver.

Definition of the Periodic Temperature for Constant Temperature Wall Conditions
For the case of constant wall temperature, as the fluid flows through the periodic domain, its temperature approaches that of the wall boundaries. However, the temperature can be scaled in such a way that it behaves in a periodic manner. A suitable scaling of the temperature for periodic flows with constanttemperature walls is [ 278]
The bulk temperature, , is defined by
where the integral is taken over the inlet periodic boundary ( ). It is the scaled temperature, , which obeys a periodic condition across the domain of length .
Definition of the Periodic Temperature Change
for Specified Heat Flux Conditions
When periodic heat transfer with heat flux conditions is considered, the form of the unscaled temperature field becomes analogous to that of the pressure field in a periodic flow:
where is the periodic length vector of the domain. This temperature gradient, , can be written in terms of the total heat addition within the domain, , as
where is the specified or calculated mass flow rate.