# Turbulent Pipe Flow Tutorial Questions **URL:** \ **Category:** Fluid Flow / CFD\ **Created:** [February 2, 2019, 6:43pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224 "2019-02-02T18:43:27Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![mas985](https://www.simscale.com/forum/letter_avatar/mas985/32/6_22734026db12803ebb3e059622ac3534.png) [@mas985](https://www.simscale.com/forum/u/mas985)\ **Post date:** [February 2, 2019, 6:43pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/1 "2019-02-02T18:43:27Z")
I was reviewing the Turbulent Pipe Flow validation project and saw something that I am not quite understanding and was hoping someone could help. If I look a the y+ plot in the Solution Fields (yPlus [node]) and based upon the chart colors I noticed that the y+ values are quite a bit below 1. More like 0.14 if I click on the wall of the pipe with the element selector. If I measure the mesh spacing from the mesh display, I get something around 4-e-4 meters which would be a y+ of about 1.4. So the mesh is showing a much larger y+ value that what the plots are showing (10x). It looks like the graphical representation is not correct. What is the explanation for this? Also, what is the difference between yPlus [node] and yPlus when choosing the results? yPlus seems to be all 0 where as yPlus [node] has values. Thanks > **[SimScale Login](https://www.simscale.com/workbench/?pid=4019193760922383455&rru=69b3cc5d-22af-4425-8b43-1ea0186df9e0&ci=ac78fa4c-dd7e-4372-9acc-3586fd90d159&ct=SOLUTION_FIELD&mt=SIMULATION_RESULT)** > > Log in to your SimScale account. SimScale makes high-fidelity engineering simulation technically and economically accessible. At any scale. In the cloud. ---
**Author:** ![jousefm](https://www.simscale.com/forum/user_avatar/www.simscale.com/jousefm/32/34908_2.png) [@jousefm](https://www.simscale.com/forum/u/jousefm)\ **Post date:** [February 2, 2019, 7:21pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/2 "2019-02-02T19:21:25Z")
Hi @mas985! There is nothing wrong with y+ well below 1 if you can afford it but being at around 1 is always recommended. Also this value depends on which turbulence model you are using and which type of flow you are investigating. So that should be fine. About the “node” question: There are two types of Data, **cell data** and **point data**. Cell data is the **‘raw’** data produced by the solver and ParaView correctly displays this by showing each cell filed with this scalar value. Point data, however, is **interpolated data** based upon cell data, this allows ParaView to display a more visually pleasing gradient. - Source: **[Post-Processing: Data Types](https://www.simscale.com/forum/t/post-processing-data-types/81139)** For the representation in the post-processing viewer let me reach out to my colleagues to make sure there is nothing broken. Will keep you up-to-date! Cheers! Jousef ---
**Author:** ![mas985](https://www.simscale.com/forum/letter_avatar/mas985/32/6_22734026db12803ebb3e059622ac3534.png) [@mas985](https://www.simscale.com/forum/u/mas985)\ **Post date:** [February 2, 2019, 8:02pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/3 "2019-02-02T20:02:31Z")
I know that a y+ below 1 is ok but what I am saying is the values on the graph do not match the calculated values from the mesh. There is a 10x difference between the two. The graph values are 1/10th the value they should be based upon the mesh layer at the wall boundary. The documentation in that tutorial even states the target is around 1 y+ which the mesh spacing is confirming. However, the y+ value graphs are indicating a value 1/10th that. ---
**Author:** ![jousefm](https://www.simscale.com/forum/user_avatar/www.simscale.com/jousefm/32/34908_2.png) [@jousefm](https://www.simscale.com/forum/u/jousefm)\ **Post date:** [February 2, 2019, 8:05pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/4 "2019-02-02T20:05:12Z")
Got it @mas985! Already reported and will let you know what the issue is as soon as possible! Best, Jousef ---
**Author:** ![mas985](https://www.simscale.com/forum/letter_avatar/mas985/32/6_22734026db12803ebb3e059622ac3534.png) [@mas985](https://www.simscale.com/forum/u/mas985)\ **Post date:** [February 2, 2019, 8:05pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/5 "2019-02-02T20:05:58Z")
Also, regarding cell vs point, so which is [node] referring to? Point data? [node] data looks to be more like cell data that is in your reference. ---
**Author:** ![jousefm](https://www.simscale.com/forum/user_avatar/www.simscale.com/jousefm/32/34908_2.png) [@jousefm](https://www.simscale.com/forum/u/jousefm)\ **Post date:** [February 2, 2019, 8:14pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/6 "2019-02-02T20:14:02Z")
Node is equal to the smooth node data. See below: \underline{\textbf{Node Data}} ![Node%20Data](https://www.simscale.com/forum/uploads/default/original/3X/d/8/d8a02bc9b596665238eec553f9dcd32a6eae28fb.png) \underline{\textbf{Raw Data}} ![Raw%20Data](https://www.simscale.com/forum/uploads/default/original/3X/3/6/36eab08628de4b7ce0e812ec3e445e3432e243f5.png) Best, Jousef ---
**Author:** ![mas985](https://www.simscale.com/forum/letter_avatar/mas985/32/6_22734026db12803ebb3e059622ac3534.png) [@mas985](https://www.simscale.com/forum/u/mas985)\ **Post date:** [February 2, 2019, 8:29pm UTC](https://www.simscale.com/forum/t/turbulent-pipe-flow-tutorial-questions/84224/7 "2019-02-02T20:29:12Z")
Thanks!