Regularization modeling for largeeddy simulation of homogeneous isotropic decaying turbulence
Geurts, B.J. and Kuczaj, A.K. and Titi, E.S. (2008) Regularization modeling for largeeddy simulation of homogeneous isotropic decaying turbulence. Journal of Physics A: Mathematical and General, 41 (34). p. 344008. ISSN 17518113

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Abstract:  Inviscid regularization modeling of turbulent flow is investigated. Homogeneous, isotropic, decaying turbulence is simulated at a range of filter widths. A coarsegraining of turbulent flow arises from the direct regularization of the convective nonlinearity in the Navier–Stokes equations. The regularization is translated into its corresponding subfilter model to close the equations for largeeddy simulation (LES). The accuracy with which primary turbulent flow features are captured by this modeling is investigated for the Leray regularization, the Navier–Stokesα formulation (NSα), the simplified Bardina model and a modified Leray approach. On a PDE level, each regularization principle is known to possess a unique, strong solution with known regularity properties. When used as turbulence closure for numerical simulations, significant differences between these models are observed. Through a comparison with direct numerical simulation (DNS) results, a detailed assessment of these regularization principles is made. The regularization models retain much of the smallscale variability in the solution. The smaller resolved scales are dominated by the specific subfilter model adopted. We find that the Leray model is in general closest to the filtered DNS results, the modified Leray model is found least accurate and the simplified Bardina and NSα models are in between, as far as accuracy is concerned. This rough ordering is based on the energy decay, the Taylor Reynolds number and the velocity skewness, and on detailed characteristics of the energy dynamics, including spectra of the energy, the energy transfer and the transfer power. At filter widths up to about 10% of the computational domainsize, the Leray and NSα predictions were found to correlate well with the filtered DNS data. Each of the regularization models underestimates the energy decay rate and overestimates the tail of the energy spectrum. The correspondence with unfiltered DNS spectra was observed often to be closer than with filtered DNS for several of the regularization models. 
Item Type:  Article 
Copyright:  © 2008 Institute of Physics 
Faculty:  Electrical Engineering, Mathematics and Computer Science (EEMCS) 
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Link to this item:  http://purl.utwente.nl/publications/65253 
Official URL:  http://dx.doi.org/10.1088/17518113/41/34/344008 
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