_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/
\n_\/
\n_\/ \u6d41\u4f53\u529b\u5b66\u30bb\u30df\u30ca\u30fc \uff12\uff10\uff10\uff15 No. \uff11\uff12
\n_\/ \uff08\u4eac\u5927\u7406\u5b66\u90e8 \u7269\u7406COE\u300c\u7269\u7406\u5b66\u306e\u591a\u69d8\u6027\u3068\u666e\u904d\u6027\u306e\u63a2\u7a76\u62e0\u70b9\u300d\u306e\u8ac7\u8a71\u4f1a\u3068\u306e\u5171\u50ac\uff09
\n_\/
\n_\/ \u65e5 \u6642 : \uff10\uff15\u5e74 \uff11\uff11\u6708 \uff12\uff11\u65e5 (\u6708) \uff11\uff15\uff1a\uff10\uff10\u301c\uff11\uff16\uff1a\uff13\uff10
\n_\/
\n_\/ \u5834 \u6240 : \uff01\uff01\u6ce8\u610f\uff1a \u5834\u6240\u304c\u3075\u3060\u3093\u3068\u306f\u7570\u306a\u308a\u307e\u3059\uff01\uff01
\n_\/ \u4eac\u5927\u7406\u5b66\u90e8\uff15\u53f7\u9928 (\u7269\u7406\u5b66\u6559\u5ba4) \u7b2c\uff12\u8b1b\u7fa9\u5ba4
\n_\/
\n_\/ \u8b1b \u5e2b\uff1a Jeremie Bec \u6c0f(Observatoire de la Cote d’Azur, France)
\n_\/
\n_\/ \u984c \u76ee\uff1a Large suspensions of inertial particles in turbulent flows
\n_\/
\n_\/ \u5185 \u5bb9 :
\n_\/ During the last ten years important progress has been made
\n_\/ on a turbulence-related issue: tools borrowed from high-energy and
\n_\/ statistical physics have been used to explain how anomalous scaling
\n_\/ arises in the dynamics of passive scalar advected by incompressible
\n_\/ turbulent flow. Much more violent phenomena take place when the
\n_\/ dynamics is dissipative: trajectories generally concentrate on
\n_\/ dynamically evolving singular sets with fractal and multifractal
\n_\/ properties.
\n_\/
\n_\/ An instance is the case of dust, droplets, bubbles or other small
\n_\/ impurities advected by turbulent flow. Such particles generally have
\n_\/ a finite size and a mass density different from the fluid. They cannot
\n_\/ be modeled by simple tracers: inertia effects are present in their
\n_\/ dynamics. In a turbulent flows, eddies are responsible act as small
\n_\/ centrifuges and eject particles leading to their concentration in the
\n_\/ low-vorticity regions of the flow. The statistical description of
\n_\/ such \u00a5emph{preferential concentrations} remains largely an open
\n_\/ question, with applications, for instance, in the growth of rain drops
\n_\/ in subtropical clouds or in the formation of planetesimals in the
\n_\/ early Solar system.
\n_\/
\n_\/ I will present some results obtained for very diluted suspensions
\n_\/ where particle-to-particle hydrodynamical interactions and retroaction
\n_\/ of the particles on the fluid are disregarded. After relaxation of
\n_\/ transients, the phase-space density of particles becomes singular with
\n_\/ non-trivial multiscaling properties. Multifractality in phase space
\n_\/ implies also multiscaling of the spatial distribution of the mass of
\n_\/ particles. Numerical simulations in homogeneous isotropic turbulent
\n_\/ flows and with heavy particles, allow the accurate determination of
\n_\/ the scaling exponents. I will finally discuss how taking into account
\n_\/ multifractal distributions of particles can be crucial in determining
\n_\/ their collision rates.
\n_\/
\n_\/ References
\n_\/ * J.Bec, “Fractal clustering of inertial particles in random flows”,
\n_\/ Phys. Fluids 15, L81 (2003). [nlin.CD\/0306049]
\n_\/ * J.Bec, “Multifractal concentrations of inertial particles in smooth
\n_\/ random flows”, J.Fluid Mech. 528 255–277 (2005). [nlin.CD\/0402024]
\n_\/ * J. Bec, A.Celani, M.Cencini & S.Musacchio, “Clustering and collisions
\n_\/ of heavy particles in random smooth flows”,
\n_\/ Phys.Fluids 17, 073301 (2005). [nlin.CD\/0407013]
\n_\/
\n_\/ \u306a\u304a\u3001\u8b1b\u5e2b\u306f\u4eac\u5927\u7406\u5b66\u90e8\u7269\u7406COE\u300c\u7269\u7406\u5b66\u306e\u591a\u69d8\u6027\u3068\u666e\u904d\u6027\u306e\u63a2\u7a76\u62e0\u70b9\u300d\u306e
\n_\/ \u62db\u8058\u7814\u7a76\u8005\u3068\u3057\u3066\u300111\/12\u304b\u308912\/4\u307e\u3067\u4eac\u5927 \u7406\u5b66\u90e8 \u7269\u7406\u5b66\u6559\u5ba4 \u6d41\u4f53\u7269\u7406\u5b66
\n_\/ \u7814\u7a76\u5ba4\u306b\u6ede\u5728\u3057\u307e\u3059\u3002
\n_\/
\n_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/
\n\u4e16\u8a71\u4eba\uff1a\u5927\u6728\u8c37 \u8015\u53f8(\u4eac\u5927\u6570\u7814)\u3001\u85e4 \u5b9a\u7fa9(\u4eac\u5927\u7406)\u3001\u677e\u672c \u525b(\u4eac\u5927\u7406)\u3001
\n\u5c71\u7530 \u9053\u592b(\u4eac\u5927\u6570\u7814)
\n\u30a2\u30c9\u30d0\u30a4\u30b6\u30fc\uff1a\u5c0f\u68ee \u609f\uff08\u4eac\u5927\u5de5\uff09\u3001\u85e4\u5742\u535a\u4e00\uff08\u4eac\u5927\u60c5\u5831\u5b66\uff09\u3001
\n\u8239\u8d8a \u6e80\u660e\uff08\u4eac\u5927\u60c5\u5831\u5b66\uff09\u3001\u6c34\u5cf6 \u4e8c\u90ce(\u540c\u5fd7\u793e\u5927\u5de5)\u3001\u4f59\u7530 \u6210\u7537\uff08\u4eac\u5927\u7406\uff09
\n\u9023\u7d61\u5148\uff1aohkitani@kurims.kyoto-u.ac.jp
\n\u30e1\u30fc\u30eb\u30ea\u30b9\u30c8\u9023\u7d61\u5148\uff1a semi-adm@kyoryu.scphys.kyoto-u.ac.jp<\/p>\n
\u623b\u308b [http:\/\/www.kyoryu.scphys.kyoto-u.ac.jp\/semi\/semi2.html]<\/p>\n","protected":false},"excerpt":{"rendered":"
_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/_\/ _\/ _\/ \u6d41\u4f53\u529b\u5b66\u30bb\u30df\u30ca\u30fc \uff12\uff10\uff10\uff15 No. \uff11\uff12 _\/ \uff08 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,27],"tags":[],"class_list":["post-385","post","type-post","status-publish","format-standard","hentry","category-16","category-27"],"_links":{"self":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts\/385","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=385"}],"version-history":[{"count":0,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts\/385\/revisions"}],"wp:attachment":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=385"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=385"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=385"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}