Response maxima in time-modulated turbulence: Direct numerical simulations

Kuczaj, A.K. and Geurts, B.J. and Lohse, D. (2006) Response maxima in time-modulated turbulence: Direct numerical simulations. Europhysics Letters, 73 (6). pp. 851-857. ISSN 0295-5075

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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 (2003) 046308). In accordance with the theory the response maximum shows only a small dependence on the 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 the phase-shift relative to the time-modulated forcing is observed. For large ω the phase shift approaches roughly 90° for the total energy and 180° for the energy dissipation rate.
Item Type:	Article
Copyright:	© 2006 IOP Science
Faculty:	Electrical Engineering, Mathematics and Computer Science (EEMCS) Science and Technology (TNW)
Research Group:	Physics of Fluids (POF) Mathematics of Computational Science (MaCS)
Link to this item:	http://purl.utwente.nl/publications/61316
Official URL:	http://dx.doi.org/10.1209/epl/i2005-10486-2
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