We seek possible statistical consequences of the way a forcing term is added to the Navier–Stokes equations in the Direct Numerical Simulation (DNS) of incompressible channel flow. Simulations driven by constant flow rate, constant pressure gradient and constant power input are used to build large databases, and in particular to store the complete temporal trace of the wall-shear stress for later analysis. As these approaches correspond to different dynamical systems, it can in principle be envisaged that these differences are reflect by certain statistics of the turbulent flow field. The instantaneous realizations of the flow in the various simulations are obviously different, but, as expected, the usual one-point, one-time statistics do not show any appreciable difference. However, the PDF for the fluctuations of the streamwise component of wall friction reveals that the simulation with constant flow rate presents lower probabilities for extreme events of large positive friction. The low probability value of such events explains their negligible contribution to the commonly computed statistics; however, the very existence of a difference in the PDF demonstrates that the forcing term is not entirely uninfluential. ... mehr

Zugehörige Institution(en) am KIT |
Institut für Strömungsmechanik (ISTM) |

Publikationstyp |
Zeitschriftenaufsatz |

Jahr |
2016 |

Sprache |
Englisch |

Identifikator |
ISSN: 0997-7546, 1873-7390 KITopen-ID: 1000054202 |

Erschienen in |
European journal of mechanics / B |

Band |
55 |

Heft |
2 |

Seiten |
286-293 |

Nachgewiesen in |
Web of Science Scopus |

Relationen in KITopen |

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