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-   -   Rotating Wind turbine rotor model step up (http://www.cfd-online.com/Forums/cfx/117531-rotating-wind-turbine-rotor-model-step-up.html)

shiyun May 10, 2013 03:36

Rotating Wind turbine rotor model step up
 
3 Attachment(s)
Hi everyone

I am doing a rotating wind turbine simulation via ANSYS CFX, I found it is difficult to find a tutorial related to this kind of model, so here I would like to share my CFX setting to those fresh people who has no idea how to set up this simulation.
MOREOVER, I also hope those real sophisticated experts can help and correct my setting as the simulation result is NOT good.

Geometry: the blade is 2.5m, the rotor is full model of dual blades.
Fluid domain:
1.Stationary cylinder---Up stream 10m, down stream 50m, Diameter 25m. 2.Rotating thin disk: radius is 0.1m longer than rotor radius, 0.1m in front and behind of the rotor.

Mesh: Structured mesh in stationary domain, unstructured mesh in rotating domain.

CFX BCs for steady state:

Material: Air ideal gas
Reference pressure: 1 atm
Turbulent model: SST


Stationary domain
Inlet: 10m/s in axial directon
Outlet: 0 Pa
FF wall: Free slip wall

Rotating domain
R speed: 320 rpm
rotor wall: No slip wall

Interface: each surface of the rotating disk domain is a individual interface connect to the Stationary fluid, use general connection ---> Frozen Rotor

However, I found the simulation result is not reasonable, eg, the fluid is discontinuous between the rotating and stationary domain, and unexpected velocity domain in wake region.

I upload the mesh and simulation result pictures. and draw out the problems.
Please give me some suggestion to improve this simulation.

shiyun May 13, 2013 01:25

anybody can help?

ghorrocks May 13, 2013 06:33

This is an FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

In this case, I suspect:
* You have not run the simulation long enough to blow the wake fully downstream.
* Is this adequately converged?
* You have a big jump in mesh size either side of the GGIs. You need to match the mesh sizes better.
* Are you plotting velocity in the stationary frame across the rotor disk? If you just plot velocity you will get "strange" results if you do not appreciate that you are looking at velocities in the local frame of reference.


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