{
  "id": "2503.08283",
  "version": "v2",
  "published": "2025-03-11T10:57:35.000Z",
  "updated": "2025-06-24T07:31:34.000Z",
  "title": "Nonlinear optimals and their role in sustaining turbulence in channel flow",
  "authors": [
    "Dario Klingenberg",
    "Rich R. Kerswell"
  ],
  "categories": [
    "physics.flu-dyn",
    "cs.CE",
    "math.OC",
    "nlin.CD"
  ],
  "abstract": "We investigate the energy transfer from the mean profile to velocity fluctuations in channel flow by calculating nonlinear optimal disturbances,i.e. the initial condition of a given finite energy that achieves the highest possible energy growth during a given fixed time horizon. It is found that for a large range of time horizons and initial disturbance energies, the nonlinear optimal exhibits streak spacing and amplitude consistent with DNS at least at Re_tau = 180, which suggests that they isolate the relevant physical mechanisms that sustain turbulence. Moreover, the time horizon necessary for a nonlinear disturbance to outperform a linear optimal is consistent with previous DNS-based estimates using eddy turnover time, which offers a new perspective on how some turbulent time scales are determined.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2025-06-24T07:31:34.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "channel flow",
      "sustaining turbulence",
      "turbulent time scales",
      "eddy turnover time",
      "initial disturbance energies"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}