Total Pressure problem in a duct
 

Hello
Please help me
I created a 2D S-duct, the contours are as follows
1.Static pressure
2.Velocity contours
3. Total pressure gradient graph

intake Velocity 20m/s
Guage pressure is taken as '0' pascals

there is flow separation and reversal at + cruvature
created a rake through the duct to find out the pressure gradient

but the total pressure should be constant in duct, only static pressure changes but i was unable to find out what physical problem is causing such as change as shown in graph