Hi Guillermo, this is neither a bug in nektar++ nor in paraview. You are using a discontinuous projection, so at the element edges, each field has two values defined by the two adjacent elements. So what you see in paraview is the actual soution. To avoid this effect, you could either increase the resolution in the respective region to reduce the discontinuity or apply a continuous projection in proprocessing, e.g. by using the "C0Projection" FieldConvert module. Cheers, Kilian Am Freitag, 20. April 2018, 20:14:27 CEST schrieb Guillermo:

Hi Kilian,

Thank you. I attach the .vtu file. I also attach the mesh (.msh.xml) and the conditions file (.xml). To find the problem I mentioned I followed these steps: Open the .vtu file and visualize the Mach number. Then, at the top left corner you should see something like the image I have attached to this email (Nozzle.png) (I am using the "Red to blue Rainbow" preset). You can see that there is a point on the domain with a Mach number value around 6.67e-01. Now use the "Hover Points on" tool from paraview and set the cursor over that node. The pop up window should indicate that the Mach number is 1.10772. Using the spreadsheet view and searching for those Mach number values you can see that its coordinates are the same.

Please, let me know if there is anything else that I can do.

Thank you.

Kind regards, Guillermo Suárez