[NRAE]

Dear all,

As recently I was born into the world of CFD and namely OpenFoam, I am quite unsure if the boundary conditions I imposed on my problem are keeping the solution from converging.

My problem, simply put, is a multiple inlet pipe turbulent flow (one outlet). The pressure is atmospheric at the inlets and I know the pressure drop and so the outlet pressure.

As boundary conditions I use:

p at the wall: zeroGradient
p at the inlet/outlet: totalPressure

U at the wall: no-slip
U at the inlet/outlet: pressureInletVelocity

I do get good results for the U field, but I cannot converge the solution past 1e-05 (residuals)

I would deeply appreciate some comments and suggestions. Thank you in advance!

Best Regards,


P.S: Last few lines of my run.log

Time = 5245

smoothSolver: Solving for Ux, Initial residual = 0.0007018282518, Final residual = 2.958226676e-06, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.0003545198219, Final residual = 1.463019906e-06, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.001171545863, Final residual = 4.967898041e-06, No Iterations 2
GAMG: Solving for p, Initial residual = 1.22858268e-05, Final residual = 6.749240303e-08, No Iterations 4
time step continuity errors : sum local = 0.004308962683, global = 7.405605908e-05, cumulative = 0.005426849098
smoothSolver: Solving for omega, Initial residual = 4.828348037e-05, Final residual = 1.617301475e-07, No Iterations 2
smoothSolver: Solving for k, Initial residual = 0.0003929569477, Final residual = 1.535229523e-06, No Iterations 2
bounding k, min: 6.075557049e-20 max: 919.2664485 average: 30.67317896
ExecutionTime = 2340.74 s ClockTime = 2346 s

Time = 5246

smoothSolver: Solving for Ux, Initial residual = 0.0007016547237, Final residual = 2.956585307e-06, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.0003544918589, Final residual = 1.462750063e-06, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.00117128006, Final residual = 4.966817581e-06, No Iterations 2
GAMG: Solving for p, Initial residual = 1.229932773e-05, Final residual = 6.736586028e-08, No Iterations 4
time step continuity errors : sum local = 0.004302080966, global = 7.339138333e-05, cumulative = 0.005500240481
smoothSolver: Solving for omega, Initial residual = 4.82731142e-05, Final residual = 1.616251747e-07, No Iterations 2
smoothSolver: Solving for k, Initial residual = 0.0003930272053, Final residual = 1.534941648e-06, No Iterations 2
bounding k, min: 1.917962781e-19 max: 919.5142253 average: 30.67442472
ExecutionTime = 2351.35 s ClockTime = 2356 s

Time = 5247

smoothSolver: Solving for Ux, Initial residual = 0.0007014774848, Final residual = 2.954904728e-06, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.0003544626055, Final residual = 1.462491573e-06, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.001171012438, Final residual = 4.965712478e-06, No Iterations 2
GAMG: Solving for p, Initial residual = 1.230198743e-05, Final residual = 6.726112248e-08, No Iterations 4
time step continuity errors : sum local = 0.004295913706, global = 7.275046518e-05, cumulative = 0.005572990946
smoothSolver: Solving for omega, Initial residual = 4.826318607e-05, Final residual = 1.615196436e-07, No Iterations 2
smoothSolver: Solving for k, Initial residual = 0.0003930984067, Final residual = 1.53462874e-06, No Iterations 2
bounding k, min: 1.384152653e-19 max: 919.7625126 average: 30.67566873
ExecutionTime = 2361.2 s ClockTime = 2366 s