Wall-bounded turbulence exhibits patterns that persist in time and space: coherent
structures. These are important for transport processes and form a conceptual framework for …

Deep reinforcement learning (DRL) is applied to control a nonlinear, chaotic system
governed by the one-dimensional Kuramoto–Sivashinsky (KS) equation. DRL uses …

Pipe flow and many other shear flows show a transition to turbulence at flow rates for which
the laminar profile is stable against infinitesimal perturbations. In this brief review the recent …

This paper aims at characterizing the bypass transition in boundary layers subject to strong
pressure gradient and curvature effects. A series of highly resolved large-eddy simulations …

Rotor-stator cavity flows are known to exhibit unsteady flow structures in the form of circular
and spiral rolls. While the origin of the spirals is well understood, that of the circular rolls is …

This paper reports several new classes of unstable recurrent solutions of the two-
dimensional Euler equation on a square domain with periodic boundary conditions. These …

In the context of linear stability analysis, considering unsteady base flows is notoriously
difficult. A generalisation of modal linear stability analysis, allowing for arbitrarily unsteady …

Recent progress in understanding subcritical transition to turbulence is based on the
concept of the edge, the manifold separating the basins of attraction of the laminar and the …

Dissipative dynamical systems characterized by two basins of attraction are found in many
physical systems, notably in hydrodynamics where laminar and turbulent regimes can …

The transient process of turbulence development and vortex breakdown from a marginal
flow state dominated by streaky velocity patterns is not only essential for understanding the …