Turbulence modification by periodically modulated scale-depending forcing

A.K. Kuczaj, B.J. Geurts, D. Lohse, W. van de Water

Research output: Contribution to conferencePaperAcademicpeer-review

Abstract

The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier-Stokes equations. The forcing is modulated via periodic energy input variations at a frequency $\omega$. Such forcing of the large-scales is shown to yield a response maximum at frequencies in the range of the inverse of the large-eddy turnover time. Time-modulated broad-band forcing is also studied in which a wide spectrum of length-scales is forced simultaneously. If smaller length-scales are explicitly agitated by the forcing, the response maximum is found to occur at higher frequencies and to become less pronounced. In case the forced spectrum is sufficiently wide, a response maximum was not observed. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/ \omega$, consistent with theoretical predictions.
Original languageEnglish
Pages-
Number of pages4
Publication statusPublished - 2006

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turbulence
direct numerical simulation
turbulent flow
Navier-Stokes equation
kinetic energy
vortices
broadband
predictions
energy

Keywords

  • EWI-7521
  • IR-63572
  • METIS-236805

Cite this

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title = "Turbulence modification by periodically modulated scale-depending forcing",
abstract = "The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier-Stokes equations. The forcing is modulated via periodic energy input variations at a frequency $\omega$. Such forcing of the large-scales is shown to yield a response maximum at frequencies in the range of the inverse of the large-eddy turnover time. Time-modulated broad-band forcing is also studied in which a wide spectrum of length-scales is forced simultaneously. If smaller length-scales are explicitly agitated by the forcing, the response maximum is found to occur at higher frequencies and to become less pronounced. In case the forced spectrum is sufficiently wide, a response maximum was not observed. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/ \omega$, consistent with theoretical predictions.",
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Turbulence modification by periodically modulated scale-depending forcing. / Kuczaj, A.K.; Geurts, B.J.; Lohse, D.; van de Water, W.

2006. -.

Research output: Contribution to conferencePaperAcademicpeer-review

TY - CONF

T1 - Turbulence modification by periodically modulated scale-depending forcing

AU - Kuczaj, A.K.

AU - Geurts, B.J.

AU - Lohse, D.

AU - van de Water, W.

PY - 2006

Y1 - 2006

N2 - The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier-Stokes equations. The forcing is modulated via periodic energy input variations at a frequency $\omega$. Such forcing of the large-scales is shown to yield a response maximum at frequencies in the range of the inverse of the large-eddy turnover time. Time-modulated broad-band forcing is also studied in which a wide spectrum of length-scales is forced simultaneously. If smaller length-scales are explicitly agitated by the forcing, the response maximum is found to occur at higher frequencies and to become less pronounced. In case the forced spectrum is sufficiently wide, a response maximum was not observed. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/ \omega$, consistent with theoretical predictions.

AB - The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier-Stokes equations. The forcing is modulated via periodic energy input variations at a frequency $\omega$. Such forcing of the large-scales is shown to yield a response maximum at frequencies in the range of the inverse of the large-eddy turnover time. Time-modulated broad-band forcing is also studied in which a wide spectrum of length-scales is forced simultaneously. If smaller length-scales are explicitly agitated by the forcing, the response maximum is found to occur at higher frequencies and to become less pronounced. In case the forced spectrum is sufficiently wide, a response maximum was not observed. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/ \omega$, consistent with theoretical predictions.

KW - EWI-7521

KW - IR-63572

KW - METIS-236805

M3 - Paper

SP - -

ER -