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-   -   Yplus and CP diagrams acceptable? (https://www.cfd-online.com/Forums/fluent/74255-yplus-cp-diagrams-acceptable.html)

Zweeper March 28, 2010 12:41

Yplus and CP diagrams acceptable?
 
2 Attachment(s)
Hello everyone.

im doing a 3d simulation at the moment and because of problems i meshed my geometries without an boundary layer.

i provided a plot of yplus and a plot of the contours of pressure. as you can see, my yplus is roughly in the range of 50-500.

my question is now, these diagrams are full of data points, i guess thats because of the rough distribution of the mesh elements over the geometry surface?

But is this affecting the accuracy of my results? if so, how much? are they totally wrong now?

Zweeper March 29, 2010 05:13

no suggestions?

Zweeper March 30, 2010 06:28

last try :(

Chris D March 30, 2010 11:52

If you're plotting y+ along a wall, then, at a given x location, there is one data point for every node in the cross-stream direction. (Maybe z in your case?) That's why the points line up.

I would think that the accuracy of you simulation will depend more on resolving gradients in the streamwise direction (i.e., the boundary layer), not the cross-stream direction. You mentioned that you're not clustering the grid near the wall to resolve the boundary layer. You should be clustering the grid if you want to have a chance at a good solution.

As far as how bad your results might be, there isn't really a "one size fits all" answer, and nobody will be able to answer this for you without at least knowing what you're actually calculating.

Zweeper March 30, 2010 12:00

thanks a lot, that's the answer i expected!


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