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Author During, G.; Josserand, C.; Krstulovic, G.; Rica, S. doi  openurl
  Title Strong turbulence for vibrating plates: Emergence of a Kolmogorov spectrum Type
  Year 2019 Publication Physical Review Fluids Abbreviated Journal Phys. Rev. Fluids  
  Volume 4 Issue 6 Pages 12 pp  
  Keywords  
  Abstract In fluid turbulence, energy is transferred from one scale to another by an energy cascade that depends only on the energy-dissipation rate. It leads by dimensional arguments to the Kolmogorov 1941 (K41) spectrum. Here we show that the normal modes of vibrations in elastic plates also manifest an energy cascade with the same K41 spectrum in the fully nonlinear regime. In particular, we observe different patterns in the elastic deformations such as folds, developable cones, and even more complex stretching structures, in analogy with spots, swirls, vortices, and other structures in hydrodynamic turbulence. We show that the energy cascade is dominated by the kinetic contribution and that the stretching energy is at thermodynamical equilibrium. We characterize this energy cascade, the validity of the constant energy-dissipation rate over the scales. Finally, we discuss the role of intermittency using the correlation functions that exhibit anomalous exponents.  
  Address [During, Gustavo] Pontificia Univ Catolica Chile, Inst Fis, Casilla 306, Santiago, Chile, Email: sergio.rica@uai.cl  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-990x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000471999200003 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 1025  
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Author Josserand, C.; Pomeau, Y.; Rica, S. doi  openurl
  Title Finite-time localized singularities as a mechanism for turbulent dissipation Type
  Year 2020 Publication Physical Review Fluids Abbreviated Journal Phys. Rev. Fluids  
  Volume 5 Issue 5 Pages 15 pp  
  Keywords  
  Abstract The nature of the fluctuations of the dissipation rate in fluid turbulence is still under debate. One reason may be that the observed fluctuations are strong events of dissipation, which reveal the trace of spatiotemporal singularities of the Euler equations, which are the zero viscosity limit of ordinary incompressible fluids. Viscosity regularizes these hypothetical singularities, resulting in a chaotic fluctuating state in which the strong events appear randomly in space and time, making the energy dissipation highly fluctuating. Yet, to date, it is not known if smooth initial conditions of the Euler equations with finite energy do or do not blow up in finite time. We overcome this central difficulty by providing a scenario for singularity-mediated turbulence based on the self-focusing nonlinear Schrodinger equation. It avoids the intrinsic difficulty of Euler equations since it is well known that solutions of this NLS equation with smooth initial conditions do blow up in finite time. When adding viscosity, the model shows (i) that dissipation takes place near the singularities only, (ii) that such intense events are random in space and time, (iii) that the mean dissipation rate is almost constant as the viscosity varies, and (iv) the observation of an Obukhov-Kolmogorov spectrum with a power-law dependence together with an intermittent behavior using structure function correlations, in close correspondence with the one measured in fluid turbulence.  
  Address [Josserand, Christophe; Pomeau, Yves; Rica, Sergio] CNRS, LadHyX, F-91128 Palaiseau, France, Email: sergio.rica@uai.cl  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-990x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000535862800004 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 1198  
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