Negative Heat Transfer Coefficients
 

Hi all,

I am modeling air flow over a vehicle. Some portions of the mesh such as tires, controllers, and motors are generating heat so I have boundary conditions at steady state temperature operation. When it appears my system has converged, I am seeing some areas of negative heat transfer coefficient. They are patchy at best but concentrated in symmetry on both sides. Can someone help me with this?

Re
 

h=q/(T_surface-T_infi)

The reason you got negative h may be is that your reference temperature is set too high. So check your reference temperature.

If the heat is from the surrounding to the surface meaning that the surface is cold, then h is negative.

Hope this is helpful...