Surface sensitivity vector is all zeros

MaxGains · August 25, 2024, 21:05

Hello,

I am currently trying to use the adjoint solver to compute the surface sensitivities of a geometry that I have parameterized with an FFD box.
When I run the adjoint solver, I expect SU2 to write values for Sensitivity_x, Sensitivity_y, and Surface_Sensitivity to surface_adjoint.csv, however, I obtain non-zero values ONLY for Surface_Sensitivity.
My adjoint solution converges correctly.

A sample row (with some columns removed) from my surface_adjoint.csv is as follows:

Code:

"PointID","x","y","Sensitivity_x","Sensitivity_y","Surface_Sensitivity"
0, 9.997500181200000e-01, -3.632896519016437e-05,  0.000000000000000e+00, 0.000000000000000e+00, -1.474964799476371e+01

If I understand correctly, Surface_Sensitivity is the dot product of the normal vector at point i with the vector [Sensitivity_x, Sensitivity_y] at point i.
How come I am obtaining zeros for Sensitivity_x and Sensitivity_y?
I have tried repeating this process on the QuickStart example and also have the same problem.

Kind regards.

MaxGains · August 27, 2024, 00:59

Using the discrete adjoint gives the full sensitivity vector.
Is this the only way to obtain the full vector?

Thanks

August 25, 2024, 21:05	Surface sensitivity vector is all zeros	#1
MaxGains New Member Viv Bone Join Date: Jun 2024 Posts: 15 Rep Power: 2	Hello, I am currently trying to use the adjoint solver to compute the surface sensitivities of a geometry that I have parameterized with an FFD box. When I run the adjoint solver, I expect SU2 to write values for Sensitivity_x, Sensitivity_y, and Surface_Sensitivity to surface_adjoint.csv, however, I obtain non-zero values ONLY for Surface_Sensitivity. My adjoint solution converges correctly. A sample row (with some columns removed) from my surface_adjoint.csv is as follows: Code: "PointID","x","y","Sensitivity_x","Sensitivity_y","Surface_Sensitivity" 0, 9.997500181200000e-01, -3.632896519016437e-05, 0.000000000000000e+00, 0.000000000000000e+00, -1.474964799476371e+01 If I understand correctly, Surface_Sensitivity is the dot product of the normal vector at point i with the vector [Sensitivity_x, Sensitivity_y] at point i. How come I am obtaining zeros for Sensitivity_x and Sensitivity_y? I have tried repeating this process on the QuickStart example and also have the same problem. Kind regards.

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August 27, 2024, 00:59		#2
MaxGains New Member Viv Bone Join Date: Jun 2024 Posts: 15 Rep Power: 2	Using the discrete adjoint gives the full sensitivity vector. Is this the only way to obtain the full vector? Thanks