Model-based control using the adjoint method applied to convectively unstable flows

Master Thesis (2025)
Author(s)

A. Plevritis (TU Delft - Aerospace Engineering)

Contributor(s)

R. P. Dwight – Mentor (TU Delft - Aerodynamics)

Nguyen Anh Khoa Doan – Graduation committee member (TU Delft - Aerodynamics)

Seven J. Hulshoff – Graduation committee member (TU Delft - Aerodynamics)

Faculty
Aerospace Engineering
More Info
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Publication Year
2025
Language
English
Graduation Date
29-09-2025
Awarding Institution
Delft University of Technology
Programme
['Aerospace Engineering']
Faculty
Aerospace Engineering
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Abstract

Flow control plays a vital role in improving efficiency in aerospace, maritime, and energy systems by delaying transition to turbulence and suppressing instabilities such as Tollmien–Schlichting waves. This work uses the Kuramoto–Sivashinsky (KS) equation as a model to study convective instabilities in boundary layers. A finite-difference discretization yields a state-space formulation, enabling systematic application of control strategies. Linear Quadratic Regulator (LQR) and adjoint-based optimization methods are developed to minimize flow perturbations. Results show LQR effectively suppresses disturbances, while adjoint-based control scales efficiently to nonlinear cases, highlighting promising avenues for future turbulence management.

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