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This paper develops a framework connecting discrete adjoint gradient-error analysis with an optimization method that uses directional error tolerances, and applies it to airfoil shape optimization governed by a conservative full-potential…

Optimization and Control · Mathematics 2026-05-19 Humberto Gimenes Macedo , Luís Felipe Bueno

The present paper numerically investigates flow control over NACA0021 (National Advisory Committee for Aeronautics) airfoil by applying a leading-edge tubercle as a passive flow control device at transitional Reynolds number (Re) regime.…

Fluid Dynamics · Physics 2022-08-25 Alok Mishra , Ashoke De

The effects of Reynolds number across $Re=1000$, $2500$, $5000$, and $10000$ on separated flow over a two-dimensional NACA0012 airfoil at an angle of attack of $\alpha=14^\circ$ are investigated through the biglobal resolvent analysis. We…

In the present study, numerical investigations were performed with optimisation to determine efficient non-uniform suction profiles to control the flow around a circular cylinder in the range of Reynolds numbers 4<Re<188.5. Several…

Fluid Dynamics · Physics 2019-06-25 James R Ramsay , Mathieu Sellier , Wei Hua Ho

An array of twelve circular-orifice synthetic jet actuators (SJAs) was used to provide the unsteady forcing required for flow separation control over a National Advisory Committee for Aeronautics (NACA) 0025 airfoil at a chord-based…

Fluid Dynamics · Physics 2024-02-20 Ali Shirinzad , Kecheng Xu , Pierre Edward Sullivan

The scope of the present project is to quantify the effects of uniform blowing and body-force damping on turbulent boundary layers subjected to a non-uniform adverse-pressure-gradient distribution. To this end, well-resolved large-eddy…

Fluid Dynamics · Physics 2018-12-11 M. Atzori , R. Vinuesa , A. Stroh , B. Frohnapfel , P. Schlatter

We develop an optimal resolvent-based estimator and controller to predict and attenuate unsteady vortex shedding fluctuations in the laminar wake of a NACA 0012 airfoil at an angle of attack of 6.5 degrees, chord-based Reynolds number of…

Fluid Dynamics · Physics 2025-08-13 Junoh Jung , Rutvij Bhagwat , Aaron Towne

We revisit a classical airfoil design problem: the search for shapes that maximize aerodynamic performance metrics, targeting the underexplored intermediate Reynolds-number regime between 1 and 3000, relevant to small animals and miniature…

Fluid Dynamics · Physics 2026-05-20 Gleb Zhdanko , Dmitry Kolomenskiy

We obtain an optimal actuation waveform for fast synchronization of periodic airfoil wakes through the phase reduction approach. Using the phase reduction approach for periodic wake flows, the spatial sensitivity fields with respect to the…

Fluid Dynamics · Physics 2023-11-28 Vedasri Godavarthi , Yoji Kawamura , Kunihiko Taira

This study investigates the effectiveness of Model Predictive Control (MPC) and Reinforcement Learning (RL) for active flow control over a NACA 4412 airfoil near static stall at Reynolds number 4*10^5. By systematically evaluating these…

We propose here a method to experimentally quantify unsteady leading-edge flow separation on aerofoils with finite thickness. The methodology relies on the computation of a leading-edge suction parameter based on measured values of the…

Fluid Dynamics · Physics 2022-05-16 Julien Deparday , Xiaowei He , Jeff D. Eldredge , Karen Mulleners , David R. Williams

The paper is concerned with a node-based, gradient-driven, continuous adjoint two-phase flow procedure to optimize the shapes of free-floating vessels and discusses three topics. First, we aim to convey that elements of a Cahn-Hilliard…

Fluid Dynamics · Physics 2022-02-10 Niklas Kühl , Thanh Tung Nguyen , Michael Palm , Dirk Jürgens , Thomas Rung

The present study proposes an active flow control (AFC) approach based on deep reinforcement learning (DRL) to optimize the performance of multiple plasma actuators on a square cylinder. The investigation aims to modify the control inputs…

This study investigates active flow control (AFC) of a 30P30N high-lift wing at a Reynolds number Re$_c$ = 450,000 and angle of attack $\alpha$ = 23$^\circ$ using wallresolved large-eddy simulations (LES). Two optimization strategies are…

Fluid Dynamics · Physics 2026-05-13 Ricard Montalà , Bernat Font , Oriol Lehmkuhl , Ricardo Vinuesa , Ivette Rodriguez

The objective of this computational study is to quantify the influence of wall-normal and angular momentum injections in suppressing laminar flow separation over a canonical airfoil. Open-loop control of fully separated, incompressible flow…

Fluid Dynamics · Physics 2017-11-28 Phillip M. Munday , Kunihiko Taira

The purpose of this work is to expand the work of Streher (2017) in order to investigate the aeroelastic instabilities generated by the flow around a moving NACA0012 airfoil. The profile has a chord length of $c=0.1 m and is exposed to a…

Fluid Dynamics · Physics 2018-07-05 Larissa B. Streher

We propose a novel model-free self-learning cluster-based control strategy for general nonlinear feedback flow control technique, benchmarked for high-fidelity simulations of post-stall separated flows over an airfoil. The present approach…

Detailed flow dissection using Dynamic Mode Decomposition (DMD) and Proper Orthogonal Decomposition (POD) is carried out to investigate the dynamics of the flow-field around a NACA-0012 aerofoil at a Reynolds number of $5\times 10^4$, Mach…

Fluid Dynamics · Physics 2018-07-25 Eltayeb ElJack , Julio Soria

A variety of shooting methods for computing fully discrete time-periodic solutions of partial differential equations, including Newton-Krylov and optimization-based methods, are discussed and used to determine the periodic, compressible,…

Optimization and Control · Mathematics 2016-08-16 Matthew J. Zahr , Per-Olof Persson , Jon Wilkening

The purpose of this work is to investigate the flow around a fixed NACA0012 airfoil profile at different angles of attack using wall-resolved LES. The profile has a chord length of c=0.1 m and is exposed to a flow at a Reynolds number of…

Fluid Dynamics · Physics 2018-07-05 Larissa B. Streher