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-   -   Wind profile (http://www.cfd-online.com/Forums/phoenics/51956-wind-profile.html)

tom September 21, 2005 08:10

Wind profile
 
Hi all,

I am using the wind profile in v3.6.1 It works fine! However there is a slight problem in that the profile changes slightly as it moves through the domain (problem with all codes). Now the change isn't a whole lot and i'm being very pedantic about this but i would really like the flow to remain stable.

In the CFX forum a person suggested that: "Maintaining a constant profile can be tricky and a constant problem. Some codes allow a feedback mechanism to perpetuate the flow through the model. What happends is that you specify an inlet condition - your profile, and then at the out let you feed back the outlet flow profile back into the inlet. This constant loop ensures that the result reaches a stable profile for a given inlet condition. This can then be input into the final model for a gived roughness and there should be no change in profile conditions throughout the model."

Can I do this with Phoenics?

Thanks for any help!


Mike September 21, 2005 12:28

Re: Wind profile
 
It seems to me that if the boundary conditons are set up correctly, and the internal numerics are consistent, then the inlet boundary-layer profile should be replicated throughout the solution domain. Library Case T306 does a fairly good job of preserving the velocity profile from inlet to outlet in the y-z solution plane.

mick September 28, 2005 10:51

Re: Wind profile
 
Yes, this sounds like an xcycle type principal. If you have a compilable version you could this up within the file ground.for group 13 and from the Q1 use a user_defined inlet condition. However to my knowledge it is not set up as a standard front end click on thing in PHOENICS.



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