[ANSYS Meshing] Error: degenerate to an invalid element

Sanghera · June 12, 2018, 11:06

Hi,

I am trying to simulate the transonic flow around an NACA 64A10 airfoil for an assignment. For this, I have one coarser mesh (y plus between 20 and 200) and one refined mesh (y plus below 1). I use the SST turbulence model.

The coarser mesh seems to work. After that, I try to change the exponential spacing (exp2 function) to a value of 1.5e-6 at the wing surface which is a guess to obtain a y plus distribution below 1. However, when I open CFX pre in the workbench for the new y plus distribution, I get an error saying:

'There was a problem importing the mesh from the requested file.
The importing process reported the following problem:

Hexahedral Element 18036 will degenerate to an invalid element:
NodeIDs: 28651, 28531, 28532, 28652, 28651, 36587, 36588, 28652'

I have been trying to fix this error for a while but did not manage yet. Help is much appreciated. Thanks.

themrdjj · November 11, 2018, 20:50

Quote:

Originally Posted by Sanghera

Hi,

I am trying to simulate the transonic flow around an NACA 64A10 airfoil for an assignment. For this, I have one coarser mesh (y plus between 20 and 200) and one refined mesh (y plus below 1). I use the SST turbulence model.

The coarser mesh seems to work. After that, I try to change the exponential spacing (exp2 function) to a value of 1.5e-6 at the wing surface which is a guess to obtain a y plus distribution below 1. However, when I open CFX pre in the workbench for the new y plus distribution, I get an error saying:

'There was a problem importing the mesh from the requested file.
The importing process reported the following problem:

Hexahedral Element 18036 will degenerate to an invalid element:
NodeIDs: 28651, 28531, 28532, 28652, 28651, 36587, 36588, 28652'

I have been trying to fix this error for a while but did not manage yet. Help is much appreciated. Thanks.

I'm having exactly the same problem as you right now. I believe you were also working on AE4202?

Did you eventually manage to fix the problem?

themrdjj · November 11, 2018, 21:34

I found a solution just now. In the "Import Mesh" window, under "Advanced Options" select "Ignore Invalid Degenerate Elements". I don't know what this actually means tbh but I finally managed to import my mesh and my simulation converged nicely and the results make sense, so that's nice!

June 12, 2018, 11:06	Error: degenerate to an invalid element	#1
Sanghera New Member Bhupinder Singh Sanghera Join Date: Jun 2018 Posts: 5 Rep Power: 7	Hi, I am trying to simulate the transonic flow around an NACA 64A10 airfoil for an assignment. For this, I have one coarser mesh (y plus between 20 and 200) and one refined mesh (y plus below 1). I use the SST turbulence model. The coarser mesh seems to work. After that, I try to change the exponential spacing (exp2 function) to a value of 1.5e-6 at the wing surface which is a guess to obtain a y plus distribution below 1. However, when I open CFX pre in the workbench for the new y plus distribution, I get an error saying: 'There was a problem importing the mesh from the requested file. The importing process reported the following problem: Hexahedral Element 18036 will degenerate to an invalid element: NodeIDs: 28651, 28531, 28532, 28652, 28651, 36587, 36588, 28652' I have been trying to fix this error for a while but did not manage yet. Help is much appreciated. Thanks.

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November 11, 2018, 21:34		#3
themrdjj New Member Daniel Join Date: Nov 2018 Posts: 24 Rep Power: 7	I found a solution just now. In the "Import Mesh" window, under "Advanced Options" select "Ignore Invalid Degenerate Elements". I don't know what this actually means tbh but I finally managed to import my mesh and my simulation converged nicely and the results make sense, so that's nice!