According to Giannetti and Luchini JFM 2007, sensitivity is the dyadic product of direct and adjoint modes. I have reproduced Giannetti and Luchini's result for Re = 50 (attached in this email) using Nektar++.
To do this multiplication, I first rename the variables of direct and adjoints modes obtained from the stability analysis. Then put them into a single file using FieldConvert. Now, rest calculations can be done inside ParaView or Visit.
With regards
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Abhishek Kumar
Assistant Professor (Research)
Centre for Fluid and Complex Systems
Coventry University, Coventry CV15FB
The United Kingdom
Web: https://sites.google.com/view/abhishekkir
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