| 摘要(英) |
Under stochastic thermal kicks, passive particles in a quiescent liquid background exhibit random walk type Brownian motion without spatiotemporal correlations. The balance between the energy pumped by the stochastic thermal kick on background molecules and the energy dissipated to the background leads to the well known Stokes-Einstein relation. Namely, the diffusivity of the passive particle is proportional to the ratio of the temperature to the drag of passive particles, and the drag coefficient linearly increases with the particle diameter.
On the other hand, the liquid with active rod-like particle suspensions is a different non-equilibrium system in which the energy is pumped by each self-propelling rod and dissipated to the highly viscous background. Through the interplay of the alignment effects from the anisotropic exclusive volume of active rods and the self-propelling from rods, the dense rod suspensions exhibit turbulence like behavior with coherent vortices and jets over a broad range of spatiotemporal scales. In the previous studies, small size passive particles have been mainly used as tracers for investigating the background flow field and its anomalous diffusion. However, increasing the passive particle size tends to suppress the response to the small scale drives from the background turbulent flow. How the passive circular rafts with different sizes diffuse in the active particle turbulence still remains an interesting unexplored issue.
In this thesis, the above unexplored issue is addressed through 2D numerical simulation. It is found that, increasing the volume fraction of active rods leads to the transition from the dilute state with nearly uncorrelated rod motion to the active turbulent state with multi-scale coherent vortices and jets. In the dilute state, the passive particle exhibit super diffusion at small time scale and normal diffusion at large time scale. The effective diffusivity remains nearly constant with increasing passive particle size, because the increasing collision rate associated with the increasing number of background rods compensates the increasing drag from the background viscous liquid. However, in the active turbulent state, the passive particle exhibits super diffusion over the entire tested time scale. The effective diffusion coefficient of the passive particle decreases with increasing size of passive particles, but less rapidly than those in the quiescent liquid background driven solely by thermal agitation. Namely, the Stokes-Einstein relation cannot be generalized to the passive particle diffusion in the active particle background. |
| 參考文獻 |
[1] Fernando Peruani, Jörn Starruß, Vladimir Jakovljevic, Lotte Søgaard-Andersen, Andreas Deutsch, and Markus Bär,Phys. Rev. Lett. 108,098102 (2012).
[2] Andrey Sokolov and Igor S. Aranson, Phys. Rev. Lett. 103, 148101(2009).
[3] H. P. Zhang , Avraham Be’er, E.-L. Florin, and Harry L. Swinney, Proc Natl Acad Sci USA 107, 13626–13630.
[4] Xiao-Lun Wu and Albert Libchaber, Phys. Rev. Lett. 84, 3017 (2000).
[5] R. Di Leonardo, L. Angelani, D. Dell’Arciprete, G. Ruocco, V. Iebba, S. Schippa, M. P. Conte, F. Mecarini, F. De Angelis, and E. Di Fabrizio, Proc Natl Acad Sci USA 107, 9541–9545.
[6] Nauman M. Qureshi, Mckaël Bourgoin, Christophe Baudet, Alain Cartellier, and Yves Gagne . , Phys. Rev. Lett. 99, 184502 (2007).
[7] Fernando Peruani, Andreas Deutsch, and Markus Bär, Phys. Rev. E. 74, 030904 (2006).
[8] Henricus H. Wensinka, Jörn Dunkelc, Sebastian Heidenreichd, Knut Drescherc, Raymond E. Goldsteinc, Hartmut Löwena, and Julia M. Yeo-mansf , Proc Natl Acad Sci USA 109, 14308–14313.
[9] P. M. Chaikin and T. C. Lubensky, Principles of condensed matter physics (Cambridge Univ Press, 2000)
[10] H. H. Wensink and H. Lowen, J. Phys. Condens. Matter 24 (2012)464130
[11] D. T. N. Chen, A. W. C. Lau, L. A. Hough, M. F. Islam, M. Goulian,
T. C. Lubensky, and A. G. Yodh, Phys. Rev. Lett. 99, 148302 (2007).
[12] Nicholas T. Ouellette, P. J. J. O’Malley and J. P. Gollub, Phys. Rev.
Lett. 101, 174504 (2008).
[13] Christopher Dombrowski, Luis Cisneros, Sunita Chatkaew, Raymond E. Goldstein, and John O. Kessler, Phys. Rev. Lett. 93, 098103 (2004).
[14] Kuo-An Liu and Lin I, Phys. Rev. E. 86, 011924 (2012).
[15] Andrey Sokolov, Igor S. Aranson, John O. Kessler, and Raymond E. Goldstein, Phys. Rev. Lett. 98, 158102 (2007).
[16] Andrey Sokolov and Igor S. Aranson, Phys. Rev. Lett. 109, 248109(2012).
[17] Juan P. Hernandez-Ortiz, Christopher G. Stoltz, and Michael D. Graham, Phys. Rev. Lett. 95 204501 (2005).
[18] Yaouen Fily and M. Cristina Marchetti, Phys. Rev. Lett. 108, 235702(2012).
[19] Luis H. Cisneros, Ricardo Cortez, Christopher Dombrowski, Raymond E. Goldstein and John O. Kessler, Exp Fluids (2007) 43, 737–753.
[20] S. Tavaddod, M.A. Charsooghi, F. Abdi, H.R. Khalesifard and R. Golestanian, Eur. Phys. J. E (2011) 34, 16. |
[Endnote RIS 格式]
[相關文章]
[文章引用]
[完整記錄]
[館藏目錄]
[檢視]
plurk
funp
live
udn
HD
myshare
netvibes
friend
youpush
delicious
baidu
Google bookmarks
del.icio.us
hemidemi
facebook
twitter
google
reddit