April 25, 2023 at 4:08 am
Chinmaya Kumar Patra
Subscriber

 

Thanks Nick for the input. In my case the reverse flow message i am getting after 60-70 time steps and it persist upto the end i.e. around 20000th time step but for each time step the solution is converged. So should i place my oultlet beyond the point currently i am considering to prevent reverse flow. A typical set of message for two time step is given below

Flow time = 0.02499868241670707s, time step = 20643

Global Courant Number [Variable Time Step Criteria] : 0.441283

Updating solution at time level N...

Global Courant Number [Explicit VOF Criteria] : 0.153555
 done.
 physical-dt  1.0000e-06

  iter  continuity  x-velocity  y-velocity  z-velocity      energy     time/iter
 370599  7.6244e-05  6.7564e-09  6.6296e-09  9.4738e-09  1.8337e-11  0:00:00   20

 Reversed flow on 19 faces of pressure-outlet 5.
 370600  2.3498e-01  1.2303e-05  1.1941e-05  1.3743e-05  3.6681e-05  0:00:01   19

 Reversed flow on 19 faces of pressure-outlet 5.
 370601  2.7168e-02  5.7825e-06  5.7242e-06  6.5056e-06  6.2679e-07  0:00:00   18

 Reversed flow on 19 faces of pressure-outlet 5.
 370602  1.7321e-02  1.6978e-06  1.6518e-06  1.8528e-06  8.3496e-08  0:00:00   17

 Reversed flow on 19 faces of pressure-outlet 5.
 370603  1.2406e-02  8.9093e-07  8.9053e-07  1.0275e-06  2.3910e-08  0:00:00   16

 Reversed flow on 19 faces of pressure-outlet 5.
 370604  9.0921e-03  7.4967e-07  7.6008e-07  8.8222e-07  7.6721e-09  0:00:00   15

 Reversed flow on 19 faces of pressure-outlet 5.
 370605  6.6246e-03  6.3146e-07  6.3900e-07  7.4103e-07  2.7183e-09  0:00:00   14

 Reversed flow on 19 faces of pressure-outlet 5.
 370606  4.7882e-03  5.0056e-07  5.0368e-07  5.8592e-07  1.1237e-09  0:00:00   13

 Reversed flow on 19 faces of pressure-outlet 5.
 370607  3.4446e-03  3.8009e-07  3.8047e-07  4.4329e-07  5.6069e-10  0:00:00   12

 Reversed flow on 19 faces of pressure-outlet 5.
 370608  2.4715e-03  2.8101e-07  2.8003e-07  3.2685e-07  3.2886e-10  0:00:00   11

 Reversed flow on 19 faces of pressure-outlet 5.
 370609  1.7704e-03  2.0421e-07  2.0288e-07  2.3757e-07  2.1352e-10  0:00:00   10

 Reversed flow on 19 faces of pressure-outlet 5.

  iter  continuity  x-velocity  y-velocity  z-velocity      energy     time/iter
 370610  1.2677e-03  1.4680e-07  1.4557e-07  1.7131e-07  1.4667e-10  0:00:00    9

 Reversed flow on 19 faces of pressure-outlet 5.
 370611  9.0807e-04  1.0479e-07  1.0380e-07  1.2298e-07  1.0215e-10  0:00:00    8

 Reversed flow on 19 faces of pressure-outlet 5.
 370612  6.5202e-04  7.4474e-08  7.3717e-08  8.8076e-08  7.2170e-11  0:00:00    7

 Reversed flow on 19 faces of pressure-outlet 5.
 370613  4.6888e-04  5.2779e-08  5.2212e-08  6.3012e-08  5.0949e-11  0:00:00    6

 Reversed flow on 19 faces of pressure-outlet 5.
 370614  3.3765e-04  3.7336e-08  3.6917e-08  4.5067e-08  3.6300e-11  0:00:00    5

 Reversed flow on 19 faces of pressure-outlet 5.
 370615  2.4338e-04  2.6383e-08  2.6072e-08  3.2238e-08  2.6007e-11  0:00:00    4

 Reversed flow on 19 faces of pressure-outlet 5.
 370616  1.7570e-04  1.8632e-08  1.8400e-08  2.3076e-08  1.8769e-11  0:00:00    3

 Reversed flow on 19 faces of pressure-outlet 5.
 370617  1.2695e-04  1.3154e-08  1.2980e-08  1.6535e-08  1.3627e-11  0:00:00    2

 Reversed flow on 19 faces of pressure-outlet 5.
 370618  9.1844e-05  9.2854e-09  9.1540e-09  1.1867e-08  9.9896e-12  0:00:00    1
!370618 solution is converged
Flow time = 0.02499968241670707s, time step = 20644

Global Courant Number [Variable Time Step Criteria] : 0.145451

Updating solution at time level N...

Global Courant Number [Explicit VOF Criteria] : 0.0483624
 done.
 physical-dt  3.1758e-07

  iter  continuity  x-velocity  y-velocity  z-velocity      energy     time/iter
 370618  9.1844e-05  9.2854e-09  9.1540e-09  1.1867e-08  9.9896e-12  0:00:00   20

 Reversed flow on 19 faces of pressure-outlet 5.
 370619  3.2095e-02  4.0304e-06  3.9061e-06  4.5219e-06  1.1961e-05  0:00:00   19

 Reversed flow on 19 faces of pressure-outlet 5.
 370620  8.1917e-03  3.4091e-06  3.4359e-06  3.6267e-06  7.1104e-08  0:00:00   18

 Reversed flow on 19 faces of pressure-outlet 5.
 370621  6.3102e-03  3.4113e-06  3.4373e-06  3.6405e-06  7.0692e-09  0:00:00   17

 Reversed flow on 19 faces of pressure-outlet 5.
 370622  4.8154e-03  2.9165e-06  2.9366e-06  3.1148e-06  1.8227e-09  0:00:00   16

 Reversed flow on 19 faces of pressure-outlet 5.
 370623  3.6150e-03  2.2834e-06  2.2971e-06  2.4394e-06  5.4397e-10  0:00:00   15

 Reversed flow on 19 faces of pressure-outlet 5.
 370624  2.6823e-03  1.7079e-06  1.7169e-06  1.8239e-06  1.9852e-10  0:00:00   14

 Reversed flow on 19 faces of pressure-outlet 5.
 370625  1.9749e-03  1.2454e-06  1.2511e-06  1.3294e-06  1.0016e-10  0:00:00   13

 Reversed flow on 19 faces of pressure-outlet 5.
 370626  1.4469e-03  8.9475e-07  8.9831e-07  9.5482e-07  6.4478e-11  0:00:00   12

 Reversed flow on 19 faces of pressure-outlet 5.
 370627  1.0573e-03  6.3702e-07  6.3922e-07  6.7990e-07  4.4939e-11  0:00:00   11

 Reversed flow on 19 faces of pressure-outlet 5.
 370628  7.7122e-04  4.5096e-07  4.5231e-07  4.8161e-07  3.1496e-11  0:00:00   10

 Reversed flow on 19 faces of pressure-outlet 5.

  iter  continuity  x-velocity  y-velocity  z-velocity      energy     time/iter
 370629  5.6189e-04  3.1810e-07  3.1891e-07  3.4002e-07  2.2032e-11  0:00:00    9

 Reversed flow on 19 faces of pressure-outlet 5.
 370630  4.0911e-04  2.2386e-07  2.2433e-07  2.3955e-07  1.5472e-11  0:00:00    8

 Reversed flow on 19 faces of pressure-outlet 5.
 370631  2.9767e-04  1.5729e-07  1.5756e-07  1.6852e-07  1.0914e-11  0:00:00    7

 Reversed flow on 19 faces of pressure-outlet 5.
 370632  2.1699e-04  1.1041e-07  1.1055e-07  1.1845e-07  7.7326e-12  0:00:00    6

 Reversed flow on 19 faces of pressure-outlet 5.
 370633  1.5822e-04  7.7444e-08  7.7516e-08  8.3213e-08  5.5071e-12  0:00:00    5

 Reversed flow on 19 faces of pressure-outlet 5.
 370634  1.1547e-04  5.4297e-08  5.4326e-08  5.8435e-08  3.9415e-12  0:00:00    4

 Reversed flow on 19 faces of pressure-outlet 5.
 370635  8.4327e-05  3.8056e-08  3.8061e-08  4.1026e-08  2.8273e-12  0:00:00    3
!370635 solution is converged
Flow time = 0.025s, time step = 20645
Specified flow time reached    flow time = 0.025, total time = 0.025