Abnormal gradient at the inlet
 

My cfd code produced abnormal gradient in the solution, see attached PARAVIEW plot.

My problem is flow past a cube incomressible)
2nd order upwind disctisation (shown in fluent literature)
green gauss gradinet,Turbulence SST-k-w

Mesh : Tet
Boundary conditions are no-slip , velocity inlet , outlet


I tried various gradient limiting schemes like MINMOD,SUPERBEE,etc


is it becouse of problem in grdient estimation or something else
Surprisingly my ist oder upwing scheme is free from this problem.
I tried NVD/TVD schemes

All predicting the drag forces correctly but solution is not smooth
problem area is inlet.