Pressure calculation problem
 

Hi, before I post about the convergence problem using simplFoam.
http://www.cfd-online.com/Forums/ope...n-problem.html
Now I guess I found the reason that induce the convergence problem.
Here is my situation.
I was calculating water flowing in two parallel pipe which are connected i with a 1mm gap n the middle as shown in the attached figure. The problem is that the pressure between two channel is a little bit different, there are some fluctuation. I think this maybe the reason that the calculation is difficult to converge. I am not sure how to solve this problem.
The reynolds number in the pipe is about 6500, but in the gap, almost laminar flow. So now I am using low-Re turbulent model to calculate.
I attached the pressure, velocity distribution along the line that cross of the middle of pipe and the gap.
Ux1 means velocity at z1 position, and Ux2 means the one at z2 position.
Sincerely hope some one can give me some advice.
Thanks.

Sorry, I continue to post the distribution of pressure.