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Modelling turbulator tape on airfoil

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Old   January 16, 2011, 15:30
Default Modelling turbulator tape on airfoil
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Dear All,
I am going to evaluate the effect and position of "Turbulator-tape" on an FX67-K170 aifoil(this is a tipical glider airfoil, used late 70s on many gliders, like LS3, Nimbus, LAK, Glassfugel, etc..). The main reason attaching Turbulator-tapes on airfoils to prevent flow separation, controlling the boundary layer. Is is commonly used on modern glider aifoils, but it was unknown at that time when the FX67-K150 and K170 aifoils were designed. The are two types: "Zig-Zag or 3D" with 0.5-0.8 mm height and "Dimple", which is a simple tape with small, about 1mm height bumps. You can see here: http://www.streifly.de/shop%20baender-e.htm how the zig-zag tape looks like. I am attaching two picturs for better understanding.I could use Ansys13.
Thanks in advance any info, help.
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File Type: jpg LS3_noppelband.jpg (86.7 KB, 25 views)
File Type: jpg LS4_zigzag.jpg (85.8 KB, 22 views)
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Old   January 16, 2011, 18:14
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Glenn Horrocks
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I am well aware of turbulators. But what are you trying to do? Assess the lift/drag on the airfoil with the turbulators in different positions around the wing? This will be tricky to model as correctly modelling the turbulators will be difficult to get accurate. There are a number of approaches (listed in approximately easiest but least accurate to hardest and most accurate):

1) Use a turbulance transition model and fix the turbulence transition point to the turbulator.
2) Use a turbulence transition model and use a rough surface at the turbulator to maybe trigger turbulence.
3) Use a turbulence transition model and use a source term to add the correct amount of turbulence intermittency at the turbulator to maybe trigger turbulence.
4) Do a full DNS model, including the turbulator roughness.
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Old   January 17, 2011, 03:43
Default Modelling turbulator tape on airfoil
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Thanks Glenn for your answer. Yes I am going to assess the lift/drag on the airfoil with the turbulators in different positions, because I have a glider with that airfoil. What does it mean "full DNS model"?
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Old   January 17, 2011, 17:43
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This will be difficult to model accurately, you are going to need some very good experimental data to get the turbulence triggering happening correctly.

Try google for a definition of DNS. I don't want to scare you
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