Lagrangian statistics for Navier-Stokes turbulence under Fourier-mode reduction: fractal and homogeneous decimations
Number of Authors: 5
2016 (English)In: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 18, 113047Article in journal (Refereed) Published
We study small-scale and high-frequency turbulent fluctuations in three-dimensional flows under Fourier-mode reduction. The Navier-Stokes equations are evolved on a restricted set of modes, obtained as a projection on a fractal or homogeneous Fourier set. We find a strong sensitivity (reduction) of the high-frequency variability of the Lagrangian velocity fluctuations on the degree of mode decimation, similarly to what is already reported for Eulerian statistics. This is quantified by a tendency towards a quasi-Gaussian statistics, i.e., to a reduction of intermittency, at all scales and frequencies. This can be attributed to a strong depletion of vortex filaments and of the vortex stretching mechanism. Nevertheless, we found that Eulerian and Lagrangian ensembles are still connected by a dimensional bridge-relation which is independent of the degree of Fourier-mode decimation.
Place, publisher, year, edition, pages
2016. Vol. 18, 113047
isotropic and homogeneous turbulence, multifractal theory, Lagrangian dynamics, intermittency
IdentifiersURN: urn:nbn:se:su:diva-137620DOI: 10.1088/1367-2630/18/11/113047ISI: 000389252900001OAI: oai:DiVA.org:su-137620DiVA: diva2:1063132