[KushNepal]

while designing the rotating wheels in ANSYS CFX I found the error of " non-zero exit code of :2"
Can anyone please help me to fix this. I am really stuck in the middle.

[-Maxim-]

please post the full error message from the out-file.

[bparrelli]

Can you describe the model a bit more? What are you trying to simulate and what BCs are you using? What is the purpose of the opening BC on the top?

[KushNepal]

Dear Brian and Maxim

I have used ANSYS 16.2 to develop a bus model with rotating wheels to measure the aerodynamic drag of the bus. I develop the wheel as a circle and I define the boundary type as wall and location as a wheel. In boundary details, I gave No slip wall and wall velocity as rotating wall of 30 m/s angular velocity. while Meshing I gave the different sizing to wheels and the bus body. I assign the top as open. so far the knowledge I gain, the top surface does not have that influence while measuring the drag as compared to the real life environment as the height of the fluid domain wall is taken from the recommended practice given by SAE. also they have suggested the top to be open. If I am wrong Your help and suggestion will be really appreciable as I am new to ANSYS CFX.

with the fix wheels I am getting the results, But when I tried to define wheels as a rotating wheels I am getting the error of Non Zero exit code
:2.
| ERROR #002100080 has occurred in subroutine CHECK_NORMV.
| Message:
| The specified velocity vector on the boundary patch
|
| wheel
|
| has a significant normal component at one or more faces. One of
| these face locations is
|
| (x,y,z) = ( 9.47980E+00,-4.39306E-01,-1.99959E-01).
| |
| The angle between the specified velocity and the element surface is
| 22.738 degrees at this face. This is considered an error because
| it implies that the mesh is moving. The following are possible
| reasons for the error message:
| 1. There is a setup error; for example, an incorrect axis of
| rotation.
| 2. There may be a meshing problem; for example, the nodes on a
| rotating surface might not lie on the surface of revolution.
| 3. The boundary is curved and the mesh is very coarse. In this
| case, you may modify the tolerance by increasing the
| expert parameter 'tangential vector tolerance wall'
| from its default of 20 degrees.

I would really appreciate for your help. Thanks in Advance.

[-Maxim-]

that error message is quite descriptive. Just work your way step by step through the suggestions.

[Chris13]

Did you check everything which is stated in the error message? There's all in there. If you did, just try to increase the tangential vector tolerance to 23 degrees as they say.

[Antanas]

Are you sure that you specified rotation axis correctly? I doubt that it should be Global Axis. You have 4 wheels and they definitely will have different axises of rotation. You can create local coordinate systems for pairs of your wheels to specify rotation axises correctly and easily.

[bparrelli]

I agree with Antanas. You definitely need to make sure your wheel axes are correctly defined. A few additional questions:

1. Can you zoom in a bit more and provide some pictures of the "bus" portion of the model, so I can see it more clearly?
2. Are you just modelling the wetted surface of the bus with rotating wheels? If so, can you show me how you're setting up your domain interface?
3. Have you successfully completed a run without the rotating wheels? Do you expect to see a significant difference in the drag coefficient?

[KushNepal]

Dear All,
I have attached the some of the picture related with the problem. I defined the axis of rotation as suggested but still I am getting the same problem.
Yes Brian, I am working on the wetted surface of the bus with rotating wheels.I have attached the picture of domain interface.

Firstly, I ran the simulation of the bus without the wheels. secondly I ran the simulation with the stationary roller. I found the drag difference of 20%. Now I am trying to figure out the difference of Drag Coefficient with rolling wheels and stationary wheels and no wheels.
But I am still facing the same error.

I hopeful yours suggestion will be much helpful in solving this problem

[KushNepal]

Also I have doubt that my wheels are not touching the ground. Does this makes the problem while assigning the boundary condition to rotating wheels.

[Antanas]

Originally Posted by KushNepal

Dear All,
I have attached the some of the picture related with the problem. I defined the axis of rotation as suggested but still I am getting the same problem.
Yes Brian, I am working on the wetted surface of the bus with rotating wheels.I have attached the picture of domain interface.

Firstly, I ran the simulation of the bus without the wheels. secondly I ran the simulation with the stationary roller. I found the drag difference of 20%. Now I am trying to figure out the difference of Drag Coefficient with rolling wheels and stationary wheels and no wheels.
But I am still facing the same error.

I hopeful yours suggestion will be much helpful in solving this problem

I don't see your rotation definition in CFX. You don't have additional coordinate frames there.

[KushNepal]

I applied the additional frame and additional domain to the rotating parts. I got the result without any error but airflow domain has not been simulated. I have attached the images regarding both cases.

Can you please suggest me why this is happening.

[KushNepal]

Some of the images I have attached regarding result and condition given for co ordinates frame

[Antanas]

Originally Posted by KushNepal

... airflow domain has not been simulated ...

What do you mean by this?