https://hal-amu.archives-ouvertes.fr/hal-03938532van Kan, AdrianAdrianvan KanDepartment of Physics [Berkeley] - UC Berkeley - University of California [Berkeley] - UC - University of CaliforniaFavier, BenjaminBenjaminFavierIRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre - AMU - Aix Marseille Université - ECM - École Centrale de Marseille - CNRS - Centre National de la Recherche ScientifiqueJulien, KeithKeithJulienDepartment of Applied Mathematics [Boulder] - University of Colorado [Boulder]Knobloch, EdgarEdgarKnoblochDepartment of Physics [Berkeley] - UC Berkeley - University of California [Berkeley] - UC - University of CaliforniaSpontaneous suppression of inverse energy cascade in instability-driven 2-D turbulenceHAL CCSD2022[NLIN] Nonlinear Sciences [physics]Favier, Benjamin2023-01-23 21:02:312023-03-24 14:53:302023-01-25 11:06:11enJournal articleshttps://hal-amu.archives-ouvertes.fr/hal-03938532/document10.1017/jfm.2022.935application/pdf1Instabilities of fluid flows often generate turbulence. Using extensive direct numerical simulations, we study two-dimensional turbulence driven by a wavenumber-localised instability superposed on stochastic forcing, in contrast to previous studies of stateindependent forcing. As the contribution of the instability forcing, measured by a parameter γ, increases, the system undergoes two transitions. For γ below a first threshold, a regular large-scale vortex condensate forms. Above this threshold, shielded vortices (SVs) emerge within the condensate. At a second, larger value of γ, the condensate breaks down, and a gas of weakly interacting vortices with broken symmetry spontaneously emerges, characterised by preponderance of vortices of one sign only and suppressed inverse energy cascade. The latter transition is shown to depend on the damping mechanism. The number density of SVs in the broken symmetry state slowly increases via a random nucleation process. Bistability is observed between the condensate and mixed SV-condensate states. Our findings provide new evidence for a strong dependence of two-dimensional turbulence phenomenology on the forcing.