[TWaung]

Hello,

I am trying to run a transient simulation of the rotating blades of a vertical axis wind turbine in CFX. My domain is thin in order to approximate a 2D simulation.

My domain looks similar to this image



There is a rotating ring shaped domain containing the blade profiles, and a stationary domain on the inside and outside of the rotating domain. The wind flows from left to right.

The problem I am encountering is that it appears that the fluid within the rotating domain is being given an angular velocity. I have run a mesh similar to the one shown but without any blade geometry and I find that the fluid in the rotating domain still has an angular velocity.

I was expecting the flow to pass straight through the rotating domain unless it was disturbed by an object like the turbine blade.

Does anyone have any suggestions on how to set up a simulation like this?

Here are some of the settings I am using.

Analysis Type: Transient
Stationary Domains: Stationary
Rotating Domain:
- Rotating at a fixed angular velocity

For the interfaces between the stationary and rotating domains, I am using:

Interface Type: Fluid Fluid
Interface Models: General Connection
Frame Change/Mixing Model: Transient Rotor Stator
Pitch Change: None
Mesh Connection Method: GGI

Thanks for any suggestions!

[ghorrocks]

You are viewing the velocity in the local frame of reference. What you are looking for is the velocity vectors in the absolute frame - so look at the variable "Velocity in Stationary Frame".

[TWaung]

Hi Glenn,

Ahh, now everything looks fine. Thanks very much!

[heatdrive]

Originally Posted by TWaung

Hello,

I am trying to run a transient simulation of the rotating blades of a vertical axis wind turbine in CFX. My domain is thin in order to approximate a 2D simulation.

My domain looks similar to this image



There is a rotating ring shaped domain containing the blade profiles, and a stationary domain on the inside and outside of the rotating domain. The wind flows from left to right.

The problem I am encountering is that it appears that the fluid within the rotating domain is being given an angular velocity. I have run a mesh similar to the one shown but without any blade geometry and I find that the fluid in the rotating domain still has an angular velocity.

I was expecting the flow to pass straight through the rotating domain unless it was disturbed by an object like the turbine blade.

Does anyone have any suggestions on how to set up a simulation like this?

Here are some of the settings I am using.

Analysis Type: Transient
Stationary Domains: Stationary
Rotating Domain:
- Rotating at a fixed angular velocity

For the interfaces between the stationary and rotating domains, I am using:

Interface Type: Fluid Fluid
Interface Models: General Connection
Frame Change/Mixing Model: Transient Rotor Stator
Pitch Change: None
Mesh Connection Method: GGI

Thanks for any suggestions!

would you please tell me,what software did you use to meshing the model? i'm doing the same project as you are, but the problem is, the solver state that my interface between stationary and rotating domain require pitch angle, but i don't know what's the value for my pitch angle...i really hope that you can help me, really appreciate your advice..

[heatdrive]

Originally Posted by ghorrocks

You are viewing the velocity in the local frame of reference. What you are looking for is the velocity vectors in the absolute frame - so look at the variable "Velocity in Stationary Frame".

i'm doing the same project as him, but the problem is, the solver state that my interface between stationary and rotating domain require pitch angle, but i don't know what's the value for my pitch angle...i really hope that you can help me, really appreciate your advice..