From the 1 of 9 linked papers with an AI index.
7 papers · 1 filter
Gradient-free learning of a closed-loop wall controller for turbulent drag reduction
Giorgio Maria Cavallazzi, Miguel Pérez Cuadrado, Alfredo Pinelli
The paper uses an evolution‑strategy optimisation to train a recurrent closed‑loop wall controller that reduces skin‑friction drag in a turbulent channel flow by about 26%, outperf…
Manifold-adapted radial basis functions for reduced-order modelling of chaotic flows
Miguel Pérez Cuadrado, Giorgio Maria Cavallazzi, Alfredo Pinelli
Chaotic systems often evolve on a low-dimensional attractor whose geometry varies from one region to another. We propose a non-intrusive reduced-order model that reads this local g…
Offline accuracy is not enough: closed-loop instability and stabilisation of a wall-sensor neural estimator in opposition control
Giorgio Maria Cavallazzi, Miguel Pérez-Cuadrado, Alfredo Pinelli
Opposition control reduces skin-friction drag by opposing the wall-normal velocity on a near-wall detection plane, but the detection-plane velocity it requires is not available fro…
Reward hacking in physical reinforcement learning revealed by turbulent drag reduction
Giorgio Maria Cavallazzi, Miguel Pérez-Cuadrado, Miguel Pérez-Cuadrado +1
Reinforcement-learning controllers optimise specified rewards, but in physical systems those rewards often capture only part of the true control objective. Three mechanisms through…
Deep reinforcement learning with spatial and temporal awareness for active boundary control of buoyancy-driven convection
Giorgio Maria Cavallazzi, Miguel Pérez Cuadrado, Miguel Pérez Cuadrado +1
Deep reinforcement learning (DRL) applied to thermal convection control consistently produces degenerate actuation: wall-temperature policies whose outputs are saturated, pseudo-ra…
Manifold-Adapted Sparse RBF-SINDy: Unbiased Library Construction and Unsupervised Discovery of Dynamical States in Turbulent Wall Flows
Miguel Perez-Cuadrado, Giorgio Maria Cavallazzi, Alfredo Pinelli
The turbulent attractor of wall bounded flows is not a structureless strange set but contains a skeleton of dynamically distinct states connected by rare directed transitions whose…