[ICEM] Surface doesn't follow curves (large farfields)

schurgelies · June 2, 2020, 21:07

I'm trying to create the airfoil hole in the fluid surface to a 2D airfoil unstructured mesh. However, for farfield distances greater then 40 (airfoil chord is 1) an error occurs (see second image).

I'm using blunt trailing edge, and creating the hole with Geometry ->Surfaces-> Trim Surface. With farfield distance less then 40 everything goes well (image 1). With greater farfields, the fluid surface invades the airfoil (image 2). Unfortunately, it doesn't seem just a visualization problem. When I create the mesh, some elements invade the airfoil, in the same way the fluid surface (image 3).

I tried to reduce triangulation and topology tolerances, and I'm already using 'Show Full' option to Surfaces. I want to use farfield distances like 100 to more accurately results, with the blunt TE (0.002 length) that look more physically accurate. Can someone help me with this?

Thanks.

https://ibb.co/VDSNBJW
https://ibb.co/kM8hX19
https://ibb.co/TrNgjK4

Gweher · July 1, 2020, 04:07

Hi Caio,

This can happen if the size of the outer domain >> size of the truncated edges. What I often do is not trimming the surface but regenerating one from curves (airfoil curves + FF).

Otherwise trim the geometry directly inside of a CAD software and import it, it will be way "cleaner" than the build in ICEM tools.

Have fun

June 2, 2020, 21:07	Surface doesn't follow curves (large farfields)	#1
schurgelies New Member Caio Join Date: Apr 2020 Posts: 1 Rep Power: 0	I'm trying to create the airfoil hole in the fluid surface to a 2D airfoil unstructured mesh. However, for farfield distances greater then 40 (airfoil chord is 1) an error occurs (see second image). I'm using blunt trailing edge, and creating the hole with Geometry ->Surfaces-> Trim Surface. With farfield distance less then 40 everything goes well (image 1). With greater farfields, the fluid surface invades the airfoil (image 2). Unfortunately, it doesn't seem just a visualization problem. When I create the mesh, some elements invade the airfoil, in the same way the fluid surface (image 3). I tried to reduce triangulation and topology tolerances, and I'm already using 'Show Full' option to Surfaces. I want to use farfield distances like 100 to more accurately results, with the blunt TE (0.002 length) that look more physically accurate. Can someone help me with this? Thanks. https://ibb.co/VDSNBJW https://ibb.co/kM8hX19 https://ibb.co/TrNgjK4

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July 1, 2020, 04:07		#2
Gweher Senior Member Gwenael H. Join Date: Mar 2011 Location: Switzerland Posts: 392 Rep Power: 20	Hi Caio, This can happen if the size of the outer domain >> size of the truncated edges. What I often do is not trimming the surface but regenerating one from curves (airfoil curves + FF). Otherwise trim the geometry directly inside of a CAD software and import it, it will be way "cleaner" than the build in ICEM tools. Have fun