Rotating Wall Velocity Error of a Fan

A subforum specific to the development of the OpenFoam-based workbenches ( Cfd https://github.com/qingfengxia/Cfd and CfdOF https://github.com/jaheyns/CfdOF )

Moderator: oliveroxtoby

User avatar
NewJoker
Veteran
Posts: 3019
Joined: Sun Oct 11, 2020 7:49 pm

Re: Rotating Wall Velocity Error of a Fan

Post by NewJoker »

@hooshsim Now I got that error with your U file. It should disappear when you use rotatingWallVelocity. It seems to be case-sensitive.
hooshsim
Posts: 108
Joined: Mon Nov 05, 2018 7:40 pm

Re: Rotating Wall Velocity Error of a Fan

Post by hooshsim »

NewJoker wrote: Fri Mar 17, 2023 3:31 pm @hooshsim Now I got that error with your U file. It should disappear when you use rotatingWallVelocity. It seems to be case-sensitive.
It's working now. Thank you again. You're a life saver. I do have couple of more questions for you since you seem to be the most knowledgeable person in here.

1. Did you run the case using single core or multiple cores? I can only run on single core. Someone suggested to install MPI like "openmpi". Not sure if it's gonna hurt my other applications using multiple cores.

2. I am also interested in the inlet or exit pressure values (mass or area averaged). Additionally, would like to know the torque generated by the fan How would you print and/or plot such entities?

I appreciate your support here and hope you have a wonderful weekend.
User avatar
NewJoker
Veteran
Posts: 3019
Joined: Sun Oct 11, 2020 7:49 pm

Re: Rotating Wall Velocity Error of a Fan

Post by NewJoker »

hooshsim wrote: Fri Mar 17, 2023 8:35 pm 1. Did you run the case using single core or multiple cores? I can only run on single core. Someone suggested to install MPI like "openmpi". Not sure if it's gonna hurt my other applications using multiple cores.
I used multiple cores. If parallelism is enabled in solver's settings and proper number of cores is specified then it must be related to your installation of OpenFOAM. Note that you are asked if you want to install openMPI when installing OpenFOAM for Windows.

This recent thread might be helpful: viewtopic.php?t=76629

hooshsim wrote: Fri Mar 17, 2023 8:35 pm 2. I am also interested in the inlet or exit pressure values (mass or area averaged). Additionally, would like to know the torque generated by the fan How would you print and/or plot such entities?
It might be easiest to do this in ParaView. The Integrate Variables filter can help with that.
hooshsim
Posts: 108
Joined: Mon Nov 05, 2018 7:40 pm

Re: Rotating Wall Velocity Error of a Fan

Post by hooshsim »

NewJoker wrote: Sat Mar 18, 2023 12:30 pm
hooshsim wrote: Fri Mar 17, 2023 8:35 pm 1. Did you run the case using single core or multiple cores? I can only run on single core. Someone suggested to install MPI like "openmpi". Not sure if it's gonna hurt my other applications using multiple cores.
I used multiple cores. If parallelism is enabled in solver's settings and proper number of cores is specified then it must be related to your installation of OpenFOAM. Note that you are asked if you want to install openMPI when installing OpenFOAM for Windows.

This recent thread might be helpful: viewtopic.php?t=76629

hooshsim wrote: Fri Mar 17, 2023 8:35 pm 2. I am also interested in the inlet or exit pressure values (mass or area averaged). Additionally, would like to know the torque generated by the fan How would you print and/or plot such entities?
It might be easiest to do this in ParaView. The Integrate Variables filter can help with that.
Thanks. Will follow your recommendations
thschrader
Veteran
Posts: 3129
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Rotating Wall Velocity Error of a Fan

Post by thschrader »

NewJoker wrote: Sat Mar 18, 2023 12:30 pm ...
It might be easiest to do this in ParaView. The Integrate Variables filter can help with that.
OK, you can compute the resulting forces (in this case lift in +y-direction) via cfdof-GUI
or paraview using successive filters.
But how can I get the location of the vector with respect to the coordinate-system?
For getting the torsion on the beam.
wing_lift.JPG
wing_lift.JPG (110.61 KiB) Viewed 778 times
User avatar
NewJoker
Veteran
Posts: 3019
Joined: Sun Oct 11, 2020 7:49 pm

Re: Rotating Wall Velocity Error of a Fan

Post by NewJoker »

thschrader wrote: Sun Mar 19, 2023 9:53 am But how can I get the location of the vector with respect to the coordinate-system?
For getting the torsion on the beam.
This solution seems to make sense: https://www.youtube.com/watch?v=3fnnIhsoPkw&t=5m10s
thschrader
Veteran
Posts: 3129
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Rotating Wall Velocity Error of a Fan

Post by thschrader »

Just found out that the moments are in the log-file... :oops: :roll:
moments.JPG
moments.JPG (32.08 KiB) Viewed 728 times
thschrader
Veteran
Posts: 3129
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Rotating Wall Velocity Error of a Fan

Post by thschrader »

Wait a minute...
For calculating the position of each force vector you must calculate the torque for
each vector, the moment sum doesnt help. Paraview still needed.

@hooshsim: sorry for using your thread.
lift_vector_position.JPG
lift_vector_position.JPG (73.07 KiB) Viewed 723 times
hooshsim
Posts: 108
Joined: Mon Nov 05, 2018 7:40 pm

Re: Rotating Wall Velocity Error of a Fan

Post by hooshsim »

thschrader wrote: Sun Mar 19, 2023 2:27 pm Wait a minute...
For calculating the position of each force vector you must calculate the torque for
each vector, the moment sum doesnt help. Paraview still needed.

@hooshsim: sorry for using your thread.

lift_vector_position.JPG
No problem Thschrader. Thanks for adding more info. Reporting function in the FC toolbar will give you force and momentum both graphically and in tabular form as well.
Post Reply