Tutorial cases run error-3D-hopper-TFM

MFiX Bug report
#1

hopper_tfm_3d_2021-09-02T173000.322836.zip (4.2 MB)

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hello, guys!
Have you meet this kind error? I tried some times, but did’t find a solution.
Can someone give me some advice!
Thanks!

#2

There is a data check that will lower the time step if the velocity gets too large. The default is 100 times the inlet velocity. Here this setting is not appropriate since your inlet velocity is very small (0.01 m/s) and it is a gravity driven case where velocity will get larger than 1m/s.

The solution is to set a large value for the maximum inlet velocity factor, say 1000.0 (Numerics> Advanced pane). This corresponds to keyword max_inlet_vel_fac = 1000.0 in the .mfx file.

Note: The relevant message in the output is:

 Message from: CHECK_VEL_BOUND
WARNING: velocity higher than maximum allowed velocity:   1.0000    
in this cell: I =   12   J =   31   K =   26 M =    1
  Eps =  0.69203E-04Us = -0.24924E-04Vs =  -1.0000    Ws =   0.0000
#3

thanks for reply, jiff! I will try this solution!

#4

Thanks jeff!
It worked, the default value(maximum inlet velocity factor) is 1, the error disappear when i set it to 100.

#5

Just a clarification: the default value of max_inlet_vel_fac is 1, but this factor multiplies a hard-coded value of 100, so the default setting means we allow the max velocity to reach 100 times the inlet velocity. When you set max_inlet_vel_fac=100, it means you allow the maximum velocity to reach 10,000 times the inlet velocity.