[aqibaziz11@gmail.com]

Greetings all,
I am a masters student of aerospace engineering and i am a learner of fluent. currently i am working on simulations for DLR F6 wingbody junction, a project present in drag prediction workshop. I have done structured meshing of my model and quality of mesh is okay. For the last 15 days i am working on fluent in order to get a converged solution for my model so that i can compare the lift coefficient, drag coefficient and surface pressure distribution with the experimental results present in drag prediction workshop. According to DPW i must get lift coefficient of 0.5 at Mach 0.75, but my solution goes to 0.5 value and then start to diverge to a small value and keeps on diverging. Following are the boundary conditions that i have set:
Inlet: pressure farfield, Mach 0.75, angle of attack 1 degree
Outlet: Pressure farfield, Mach 0.75, angle of attack of 1 degree
Side: Pressure farfield, Mach 0.75, angle of attack of 1 degree
Symmetry: Symmetry
i have used courant number of 0.5, i have used sparalat Allmaras model of turbulance, density based solver.
After some iterations, console window says negative nut value found in 2 cells after linear solve and sometimes 3 or 4. i have completed 12000 iterations but still i am not able to converge my solution to any single value. it just keep getting down and after some time starts to go up but no stable value achieved yet.
If you know the solution of this problem or you have any helpful suggestion for me then reply me to overcome this problem. Thanks
Regards