Effect of gradient scheme on Nusselt Number
 

Hi,

i am simulating laminar flow with heat transfer in a duct and i am using structure type of mesh.

i used solve/set/expert to get Temperature gradient and based on that i defined local Nusselt Number.
the problem is when i changed the gradient schemes from Green-Gauss cell based to Green-Gauss node based then Averaged Nusselt number (Area Weighted Average ) changed by 15% but there is no change in local nusselt number, how is this possible? i am totally confused.

am i doing something wrong? pease suggest me.

Thank you,
Kind Regards,
Srv