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Article
The fluidic pinball with symmetric forcing displays steady, periodic, quasi-periodic, and chaotic dynamics
We numerically investigate the fluidic pinball under symmetric forcing and find seven flow regimes under different rotation speeds. The fluidic pinball consists of three rotatable cylinders placed at the verti...
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Chapter
Turbulence Control: From Model-Based to Machine Learned
Flow analysis, modeling, and control are at the heart of engineering applications: aeronautics, airborne and ground transport, wind power generation, and industrial processes, to cite a few examples (Brunton a...
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Chapter
Evolutionary Machine Learning in Control
This chapter aims to give an overview of recent applications of Evolutionary Machine Learning (EML) to control including opportunities and challenges. Control is at the heart of engineering applications. Examp...
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Article
Open AccessAerodynamic optimization of a generic light truck under unsteady conditions using gradient-enriched machine learning control
We present the first machine-learned multiple-input multiple-output aerodynamic feedback control under varying operating conditions. Closed-loop control is relevant to many fluid dynamic applications ranging f...
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Article
Open AccessA Fast-Converging Particle Swarm Optimization through Targeted, Position-Mutated, Elitism (PSO-TPME)
We improve convergence speed by two orders of magnitude and the global exploration capabilities of particle swarm optimization (PSO) through targeted position-mutated elitism (TPME). The proposed fast-convergi...
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Article
Artificial intelligence in fluid mechanics
Recent progress in machine learning and big data not only forms a new research paradigm, but also provides opportunity to solve grand challenges in fluid mechanics. Following the disciplinary development, this...
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Article
Bayesian optimization for active flow control
A key question in flow control is that of the design of optimal controllers when the control space is high-dimensional and the experimental or computational budget is limited. We address this formidable challe...
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Article
Genetic-algorithm-based artificial intelligence control of a turbulent boundary layer
An artificial intelligence (AI) open-loop control system is developed to manipulate a turbulent boundary layer (TBL) over a flat plate, with a view to reducing friction drag. The system comprises six synthetic...
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Chapter and Conference Paper
Large-Eddy Simulation on Jet Mixing Enhancement Using Unsteady Minijets
Minijet is one of the most promising active methods for the enhancement of jet mixing. The injection of minijets into a turbulent jet before the jet exit may have multiple impacts on the jet mixing structure. ...
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Chapter and Conference Paper
Artificial Intelligence Control of a Turbulent Jet
An artificial intelligence (AI) control system is developed to manipulate a turbulent jet targeting maximal mixing. The control system consists of sensors (two hot-wires), genetic programming for evolving the ...
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Chapter and Conference Paper
Closed-Loop Drag Reduction Over a D-Shaped Body Via Coanda Actuation
Up to 40% drag reduction was achieved for a D-shaped cylinder in an experiment with robust model-based closed-loop control. The flow is actuated with on-off jet slots blowing in the stream-wise direction over ...
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Chapter
Active Flow Control Experiments on a High-Lift Configuration
The present study investigates the lift gains generated by the superposition of a periodic actuation component onto a steady component on an airfoil with a highly deflected Coanda flap. The presented results a...
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Article
Open AccessDrag Reduction and Energy Saving by Spanwise Traveling Transversal Surface Waves for Flat Plate Flow
Wall-resolved large-eddy simulations are performed to study the impact of spanwise traveling transversal surface waves in zero-pressure gradient turbulent boundary layer flow. Eighty variations of wavelength, ...
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Chapter and Conference Paper
Closed-Loop Turbulence Control-From Human to Machine Learning (and Retour)
Feedback turbulence control is a rapidly evolving, interdisciplinary field of research. The range of current and future engineering applications of closed-loop turbulence control has truly epic proportions, in...
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Chapter and Conference Paper
Reduced-Order Modeling of the Fluidic Pinball
The fluidic pinball is a geometrically simple wake flow configuration with three rotating cylinders on the vertex of an equilateral triangle. Yet, it remains physically rich enough to host a range of interacti...
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Chapter
Unstable Periodically Forced Navier–Stokes Solutions–Towards Nonlinear First-Principle Reduced-Order Modeling of Actuator Performance
We advance the computation of physical modal expansions for unsteady incompressible flows. Point of departure is a linearization of the Navier–Stokes equations around its fixed point in a frequency domain form...
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Article
Jet mixing optimization using machine learning control
We experimentally optimize mixing of a turbulent round jet using machine learning control (MLC) following Li et al. (Exp Fluids 58(article 103):1–20, 2017). The jet is manipulated with one unsteady minijet blo...
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Article
Cluster-based control of a separating flow over a smoothly contoured ramp
The ability to manipulate and control fluid flows is of great importance in many scientific and engineering applications. The proposed closed-loop control framework addresses a key issue of model-based control...
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Article
Drag reduction of a car model by linear genetic programming control
We investigate open- and closed-loop active control for aerodynamic drag reduction of a car model. Turbulent flow around a blunt-edged Ahmed body is examined at
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Article
Open AccessOn the need of mode interpolation for data-driven Galerkin models of a transient flow around a sphere
We present a low-dimensional Galerkin model with state-dependent modes capturing linear and nonlinear dynamics. Departure point is a direct numerical simulation of the three-dimensional incompressible flow aro...
