Understanding y+ colouring in Solution Fields

Using SimScale
1

I have in a simulation a view of y+ (in Solution Fields). e.g. in this project: SimScale Login
The colouring I don’t understand. It looks y+ is always zero (using Inspect Point), but the colouring is changing. See these two grabs:

Inspect Point at z=0.47:

afbeelding
afbeelding493×510 10.2 KB

Inspect Point at z=0.68:

afbeelding
afbeelding485×503 10.8 KB

So how do I interpret the y+ graph colouring? Thanks for your help.

is there some extrapolation happening form the first layer midpoint y+ value to the wall?

<changing the ledgend min and max values also has non-understanable behavoir in the colouring, IMHO>

All the best,

2

Can someone help me with this? How do I read the y+. Is the generation of graphics perhaps doing some interpolation and that gives these strange coloring?

3

I hoep this link works:

Open Project → Simulations → Basis-CFD-P(10),mesh=newmeer,askop=13,roede=24
Simulation runs → Run1 → Solution Fields → Y-Plus(Y+) → camera View: Y-Plus

So the coloring does not really match when looking at the ‘Inspect point’ values.

What is happening? I seem to have problem with my simulation and people direct me to checking the y+ value, but I am (I think) not really able to determine the values of y+, or is Inspect Point the only way to check and not the graphing?

Thanks for your help.

6

And additionally. ‘Inspect Point’ can not be used in the ‘free/community’ account. So in most cases I can only use the coloring (accept when the simulation is still running).

8

Any help? When using Solution Fields → Cutting Plane → Y-Plus (y+) looks not to render the coloring correct.

I think (but hopefully someone can agree with that) that Iso Surface/Volume renders the surface/volume boundaries correct? (One though can’t change the Iso value range in Iso Volume when in Community account…).

I really hope someone can help me with understanding this behavoir. Thanks!

10

y+, although unitless, is a field that gives you an indication of distance of the cell to the wall. The main use for it is to understand the y+ value of the first cell off the wall, so typically users only observe y+ via “Parts color”.

Inspecting y+ via cutting plane and other filters usually does not make sense.

Side comment: inspect point is available for community accounts, however you have extrapolated your 10 simulations quota, so your results do not contain quantitative information, thus inspect point is disabled.

11

I expected that only the first layer was important (and I assume the importants is at mid height of that layer; as that is where calculation happens). So reading Ihttps://www.simscale.com/docs/tutorials/post-processing-solid-mechanics-simulations/; I see that I need to set ‘Rendering mode’ at ‘Surfaces’.

Thanks for this help!

12

Perhaps add this ‘Parts Color’ also in this web page of SimScale: