Gradient of field obtained thro' UDS transport eqn is discontinuous at interfaces
 

Hello,
I'm solving UDS transport equations in Fluent for the vector potential for a solenoid. AC current components in the copper coil constitute the source terms for the equations. Diffusivities for the different materials (air, Copper and Aluminium) are provided through UDF.

At the interface , b/w surrounding air and Copper ; b/w copper and Aluminum, there is a marked, sharp discontinuity in the gradient of the vector potential field (i.e. solution of UDS transport equation) though the vector potential field (i.e. solution field) itself is continuous. I do not know where i'm going wrong.

I'm using C_UDSI_G to obtain the gradients and CFD post for viewing the results.

Thank you in advance