[bala1609]

im doing my master thesis, in that i have created the model in inventor and meshed in icem cfd after that i have imported to cfx pre but how can i do transform mesh -->scale -->uniform i want to rescale my geometry, i dont know how to create the coorinate axis in the center of the model

[Lance]

Before you scale your model do
transform mesh/transformation: translation (move your cylinder so that the origin is in center.)

or just move it in icem before importing it to CFX - all easy solutions.

[bala1609]

my analysis is flow over a spinning cylinder which is place in a tunnel. i have attached the image of the model so can you help me with that how i can rescale the model. my tunnel dimension is 4m in length 1m in breadth and height and the interface is placed 1m from the inlet and the cylinder of length 0.5m is placed in the interface.

[bala1609]

In Analysis 'Flow Analysis 1' - Domain Interface 'Domain Interface 1': Pitch Change option 'Automatic' is not valid if side 1 or 2 of the interface has a 360 degree or greater pitch angle, zero radius, mesh faces normal and parallel to the rotation axis, or mesh faces at the hub curve (low radial or axial position) which are thin in the radial or axial direction.



im getting this warning how we can over come this warning
my cylinder is spinning at 10rev/s and air flows through the tunnel at rate of 10m/s

[Gert-Jan]

If you are trying to solve the flow around a spinning cylinder, then your tunnel should be fixed (no velocity), and the cilinder should have an angular velocity. In that case your tunnel doesn't need an interface.

If you do need an interface, then your problem description is unclear.

[bala1609]

My tunnel is fixed but Inlet condition of the tunnel is 10m/s and my cylinder is rotating at angular velocity 10rev/s and I have attached my geometry so I must define the interface.

[Gert-Jan]

OK. I checked your figure now. And it looks like you have put your cilinder inside a cilindrical volume. But that is unnecessary. If you just put your bar in the tunnel and apply a rotational velocity, then you are done.

If you want to stick to this setup, use 'Frozen rotor' and 'none' for the pitch change option.

[bala1609]

That is not cylindrical volume that is interface created to connect the tunnel and cylinder.

[Gert-Jan]

As I already mentioned........ If you want to stick to this setup (with this unnecessary interface), use 'Frozen rotor' and 'none' for the pitch change option.

[bala1609]

i have tried as you told but the stimulation stops and showed the message like return code 1

[Gert-Jan]

There is a division by zero. Even CFX can't handle that. :-(

With these basic simulations, CFX will only crash if your setup is wrong. So please carefully check everything if everything makes sense. If you can't find it, share your ccl.

[bala1609]

how can i share my file. format is not supporting

[Gert-Jan]

Upload your output file (.out).

[bala1609]

I’m having only .def file but I can’t attach the file in this site. So can you mail me so that I can share my file through email my mail is is saibala16 @gmail.com

[Gert-Jan]

That is untrue.

If you have performed a succesfull simulation, you will get a results file (.res) and an output file (.out).
If you have performed an unsuccesfull simulation, you will only get an output file (.out).

I am sure you have it since the picture you showed is text in the window from the solver manager. This text is written to the .out-file. So, please look more carefull on your computer.

It could be that you work in workbench and that you didn't save you project after the crash. Then it could be that the outfile is deleted. I don't know since I hardly use Workbench.

If so, rerun and save your project. Then send the out-file. Alternatively, run the simulation, select all text in the text window of the solver manager, and copy it to a text file. Shouldn't be too difficult.

[ghorrocks]

Why is there an interface? I see no reason for an interface to be present. Gert-Jan has already discussed this. For a spinning cylinder just apply a tangential velocity on the walls of the cylinder. We should write a FAQ on this, this is a very common question.....

I also note little chamfers in the corners of your mesh. These are going to cause convergence problems. You need to go back to your meshing software and remesh to remove these chamfers. These are likely to be the cause of your convergence difficulties.