Acceleration statistics of heavy particles in turbulence

✍ Scribed by Bec, J. (author);Biferale, L. (author);Boffetta, G. (author);Celani, A. (author);Cencini, M. (author);Lanotte, A. (author);Musacchio, S. (author);Toschi, F. (author)

• Book ID: 120115981
• Publisher: Cambridge University Press
• Year: 2006
• Tongue: English
• Weight: 198 KB
• Volume: 550
• Category: Article
• ISSN: 0022-1120
• DOI: 10.1017/S002211200500844X

✦ Synopsis

We present the results of direct numerical simulations of heavy particle transport in homogeneous, isotropic, fully developed turbulence, up to resolution 512 3 (R λ ≈ 185). Following the trajectories of up to 120 million particles with Stokes numbers, St, in the range from 0.16 to 3.5 we are able to characterize in full detail the statistics of particle acceleration. We show that: (i) the root-mean-squared acceleration a rms sharply falls off from the fluid tracer value at quite small Stokes numbers; (ii) at a given St the normalized acceleration a rms /( 3 /ν) 1/4 increases with R λ consistently with the trend observed for fluid tracers; (iii) the tails of the probability density function of the normalized acceleration a/a rms decrease with St. Two concurrent mechanisms lead to the above results: preferential concentration of particles, very effective at small St, and filtering induced by the particle response time, that takes over at larger St.