Free stream temperature in convective bc
 

I'm trying to solve the case of a fluid flow inside a tube using CFD solver with convective bc for fluid side surface of the tube.
As the boundary conditions take both inlet and free stream temperatures along with velocity at the inlet, i am confused with values of to be given for inlet and free stream temperatures. i am clear with the value of inlet temperature. It will be very useful for me if any body helps me in taking appropriate value for free stream temperature and physical concept behind it in the case said above.

Vivek, if the outer surface of your tube is exposed to the atmosphere, the free stream temperature will the ambient temperature. This is because the outer surface temperature of the tube will found out by fluent. So, the temperature difference between this surface temperature and the temperature of air surrounding it (i.e. ambient temp if your tube is exposed to atmosphere) will act as the potential for heat transfer.

Thank you dreamz...I have another query....What if we are trying to give convective bc for the coolant tube's fluid side inside an aerofoil , Where conjugate heat transfer is expected to take place. Then the sorrounding temperature exact value around tube cant be determined right sir? Coolant carries heat from the aerofoil and its temperature gradually increases as coolant reaches its outlet. Heat flux is provided for the external surface of aerofoil. It will be very useful for me if any body helps me in taking appropriate value for free stream temperature and physical concept behind it in the case said above.

regards
vivek