Hicks-Henne Bump functions nomenclature

David_002 · May 12, 2024, 15:46

Hello guys,
I was trying to fully understand the "Unconstrained shape design of a transonic inviscid airfoil at a cte. AoA" tutorial but i find some trouble in the definition of the set of hicks-henne bump functions.

The explanation for its nomenclature is the following:

"The first value in the parentheses is the variable type, which is 1 for a Hicks-Henne bump function. The second value is the scale of the variable (typically left as 1.0). The name between the vertical bars is the marker tag where the variable deformations will be applied. Only the airfoil surface will be deformed in this problem. The final two values in the parentheses specify whether the bump function is applied to the upper (1) or lower (0) side and the x-location of the bump between 0 and 1 (we assume a chord of 1.0 for the Hicks-Henne bumps), respectively."

However, they are defined as following ( 30, 1.0 | airfoil | 0, 0.05 ).

Why is that 30 in the begining if the explanations says that it should be a 1?

Also, it defines bump locations from 0.05 to 0.095 (in a chord from 0 to 1) for upper and lower airfoil surface. This ads to 36 variables, however when running the program it says that there are 38 variables. Are leading and trailing edge also considered variables or what could this be?

Thank you for your time and help.

David Vergara.

Tongtong1919 · May 17, 2024, 21:42

Hi David,

I have encountered the issue you are facing before. Unfortunately, I cannot find the document where I recorded my research at that time. However, I can share what remains in my memory, which might serve as a reference. SU2 is a great tool, but the documentation is really lacking, and the official tutorials are few and far between (no more complaints from me). Anyway, to get to the point, (30, 1.0 | airfoil | 0, 0.05). Here is the explanation for these parameters:

30: This is somewhat like a code that tells SU2 to call the built-in Hicks-Henne function.
1.0: This parameter should be a coefficient (I don't remember very clearly because I have never changed this value). This value combines with DV_VALUE to get the final change value.
airfoil: This represents the airfoil boundary (the grid file should have the corresponding name).
0: This represents the lower contour of the 2D airfoil.
0.5: This represents the normalized X direction distance (this is a general X direction).
I hope this can help you. ^^

May 12, 2024, 15:46	Hicks-Henne Bump functions nomenclature	#1
David_002 New Member Join Date: Mar 2024 Posts: 15 Rep Power: 2	Hello guys, I was trying to fully understand the "Unconstrained shape design of a transonic inviscid airfoil at a cte. AoA" tutorial but i find some trouble in the definition of the set of hicks-henne bump functions. The explanation for its nomenclature is the following: "The first value in the parentheses is the variable type, which is 1 for a Hicks-Henne bump function. The second value is the scale of the variable (typically left as 1.0). The name between the vertical bars is the marker tag where the variable deformations will be applied. Only the airfoil surface will be deformed in this problem. The final two values in the parentheses specify whether the bump function is applied to the upper (1) or lower (0) side and the x-location of the bump between 0 and 1 (we assume a chord of 1.0 for the Hicks-Henne bumps), respectively." However, they are defined as following ( 30, 1.0 \| airfoil \| 0, 0.05 ). Why is that 30 in the begining if the explanations says that it should be a 1? Also, it defines bump locations from 0.05 to 0.095 (in a chord from 0 to 1) for upper and lower airfoil surface. This ads to 36 variables, however when running the program it says that there are 38 variables. Are leading and trailing edge also considered variables or what could this be? Thank you for your time and help. David Vergara.

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May 17, 2024, 21:42		#2
Tongtong1919 New Member Tongtong Join Date: Jan 2024 Posts: 9 Rep Power: 2	Hi David, I have encountered the issue you are facing before. Unfortunately, I cannot find the document where I recorded my research at that time. However, I can share what remains in my memory, which might serve as a reference. SU2 is a great tool, but the documentation is really lacking, and the official tutorials are few and far between (no more complaints from me). Anyway, to get to the point, (30, 1.0 \| airfoil \| 0, 0.05). Here is the explanation for these parameters: 30: This is somewhat like a code that tells SU2 to call the built-in Hicks-Henne function. 1.0: This parameter should be a coefficient (I don't remember very clearly because I have never changed this value). This value combines with DV_VALUE to get the final change value. airfoil: This represents the airfoil boundary (the grid file should have the corresponding name). 0: This represents the lower contour of the 2D airfoil. 0.5: This represents the normalized X direction distance (this is a general X direction). I hope this can help you. ^^