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Response maxima in time-modulated turbulence: Direct Numerical Simulations

Arkadiusz K. Kuczaj·Bernard J. Geurts·Detlef Lohse
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Abstract

The response of turbulent flow to time-modulated forcing is studied by direct numerical simulations of the Navier-Stokes equations. The large-scale forcing is modulated via periodic energy input variations at frequency $ω$. The response is maximal for frequencies in the range of the inverse of the large eddy turnover time, confirming the mean-field predictions of von der Heydt, Grossmann and Lohse (Phys. Rev. E 67, 046308 (2003)). In accordance with the theory the response maximum shows only a small dependence on the Reynolds number and is also quite insensitive to the particular flow-quantity that is monitored, e.g., kinetic energy, dissipation-rate, or Taylor-Reynolds number. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/ω$. For frequencies beyond the range of maximal response, a significant change in phase-shift relative to the time-modulated forcing is observed.

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Arkadiusz K. Kuczaj, Bernard J. Geurts, Detlef Lohse. 2005-09-24. Response maxima in time-modulated turbulence: Direct Numerical Simulations. https://doi.org/10.1209/epl%2Fi2005-10486-2

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