{"id":1002,"date":"2018-09-12T16:53:25","date_gmt":"2018-09-12T07:53:25","guid":{"rendered":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/?p=1002"},"modified":"2018-09-12T16:55:31","modified_gmt":"2018-09-12T07:55:31","slug":"%e6%b5%81%e4%bd%93%e5%8a%9b%e5%ad%a6%e3%82%bb%e3%83%9f%e3%83%8a%e3%83%bc","status":"publish","type":"post","link":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/?p=1002","title":{"rendered":"\u6d41\u4f53\u529b\u5b66\u30bb\u30df\u30ca\u30fc"},"content":{"rendered":"<p>\u6d41\u3000\u4f53\u3000\u529b\u3000\u5b66\u3000\u30bb\u3000\u30df\u3000\u30ca\u3000\u30fc<\/p>\n<p>(\u4eac\u90fd\u5927\u5b66\u5fdc\u7528\u6570\u5b66\u30bb\u30df\u30ca\u30fc(KUAMS)\u3068\u306e\u5171\u50ac)<\/p>\n<p>\u65e5\u6642:\u00a0 \uff19\u6708\uff11\uff14\u65e5\uff08\u91d1\uff09 \uff11\uff15\uff1a\uff10\uff10 \u304b\u3089 \uff11\uff16\uff1a\uff13\uff10<\/p>\n<p>\u5834\u6240:\u00a0 \u4eac\u5927 \u7406\u5b66\u7814\u7a76\u79d1 \u7269\u7406\u5b66\u6559\u5ba4(\u7406\uff15\u53f7\u9928)\u3000\uff14\uff10\uff11\u53f7\u5ba4<\/p>\n<p>\u8b1b\u5e2b\uff1a Uriel Frisch \u6c0f<br \/>\nLaboratoire Lagrange, Observatoire and Universite Cote d&#8217;Azur<br \/>\nNice, France<\/p>\n<p>\u8b1b\u6f14\u984c\u76ee\uff1aThe mathematical and numerical construction of<br \/>\nturbulent solutions for the 3D incompressible Euler<br \/>\nequation and its perspectives<\/p>\n<p>\u8b1b\u6f14\u8981\u65e8\uff1a<\/p>\n<p>Starting with Kolmogorov\u2019s 1941 (K41) work, infinite Reynolds number<br \/>\nflow is known to have velocity increments over a small distance r that<br \/>\nvary roughly as the cubic root of r. Formally,\u00a0 such\u00a0 flow\u00a0 is\u00a0 expected\u00a0 to<br \/>\nsatisfy\u00a0 Euler\u2019s\u00a0 partial differential\u00a0 equation,\u00a0 but\u00a0 the\u00a0 flow\u00a0 being<br \/>\nnot\u00a0 spatially differentiable, the equation is satisfied only in<br \/>\na distributional sense. Since Leray\u2019s 1934 work, such solutions are called<br \/>\nweak. Actually\u00a0 they\u00a0 were\u00a0 already\u00a0 present\u00a0 \u2013very\u00a0 briefly\u2013\u00a0 in<br \/>\nLagrange\u2019s 1760\/1761 work on non-smooth solutions of the wave equation.<br \/>\nA\u00a0 major\u00a0 breakthrough\u00a0 has\u00a0 happened\u00a0 recently: mathematicians\u00a0 succeeded<br \/>\nin\u00a0 constructing\u00a0 rigourously\u00a0 weak solutions\u00a0 of\u00a0 the\u00a0 Euler\u00a0 equation<br \/>\nwhose\u00a0 spatial\u00a0 regularity\u00a0 \u2013measured by their H\u00f6lder continuity exponent\u2013<br \/>\nis arbitrarily close to the value predicted by K41 (Isett 2018), Buckmaster et<br \/>\nal. 2017). Furthermore these solutions present the anomalous energy dissipation<br \/>\ninvestigated by Onsager in 1949 (Ons49). We shall highlight some aspects of<br \/>\nthe derivation of these results which took about ten years and was started<br \/>\noriginally by Camillo de Lellis and Laszlo Szekelyhidi and continued with a<br \/>\nnumber\u00a0 of\u00a0 collaborators.\u00a0 On\u00a0 the\u00a0 mathematical\u00a0 side\u00a0 the derivation makes<br \/>\nuse of techniques developed by Nash (1954) for isometric embedding and by Gromov<br \/>\n(1986, 2017) for convex\u00a0 integration.\u00a0 Fortunately,\u00a0 many\u00a0 features\u00a0 of\u00a0 the<br \/>\nderivation\u00a0 have\u00a0 a\u00a0 significant\u00a0 fluid\u00a0 mechanical\u00a0 content.\u00a0 In particular<br \/>\nthe successive introduction of finer and finer flow structures, called Mikados<br \/>\nby Daneri and Szekelyhidi (2017) because\u00a0 they\u00a0 are\u00a0 slender\u00a0 and jetlike.<br \/>\nThe Mikados generate Reynolds stresses on larger scales; they can be chosen<br \/>\nto cancel discrepancies between approximate and exact solutions of the Euler<br \/>\nequation. A particular engaging aspect of the construction of weak solutions<br \/>\nis its flexibility. The Mikados can be chosen not only to\u00a0 reproduce\u00a0 K41\/Ons49<br \/>\nselfsimilar\u00a0 turbulence,\u00a0 but\u00a0 also\u00a0 to synthesize\u00a0 a\u00a0 large\u00a0 class\u00a0 of<br \/>\nturbulent\u00a0 flows,\u00a0 possessing,\u00a0 for example,\u00a0 small-scale\u00a0 intermittency<br \/>\nand\u00a0 multifractal\u00a0 scaling. This huge playground must of course be explored<br \/>\nnumerically for testing all manners of physical phenomena and theories, a<br \/>\nprocess being started in a collaboration between Leipzig, Nice, Kyoto and Rome.<\/p>\n<p>(in collaboration with\u3000Laszlo Szekelyhidi,Department of Mathematics,<br \/>\nUniversity of Leipzig, Germany\u3000and\u3000Takeshi Matsumoto,Department of<br \/>\nPhysics, Kyoto University, Japan)<\/p>\n<p>+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;<wbr \/>+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;+&#8211;<br \/>\n\u4e16\u8a71\u4eba\uff1a\u5c71\u7530 \u9053\u592b(\u4eac\u5927\u6570\u7406\u7814)\uff0c \u7af9\u5e83 \u771f\u4e00\uff08\u4eac\u5927\u6570\u7406\u7814\uff09\uff0c<br \/>\n\u85e4 \u5b9a\u7fa9(\u4eac\u5927\u7406)\uff0c\u677e\u672c \u525b(\u4eac\u5927\u7406)<br \/>\n\u9023\u7d61\u5148\uff1a\u5c71\u7530\u9053\u592b\u00a0yamada_at_kurims.kyoto-u.ac.jp<br \/>\n==============================<wbr \/>===========================<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6d41\u3000\u4f53\u3000\u529b\u3000\u5b66\u3000\u30bb\u3000\u30df\u3000\u30ca\u3000\u30fc (\u4eac\u90fd\u5927\u5b66\u5fdc\u7528\u6570\u5b66\u30bb\u30df\u30ca\u30fc(KUAMS)\u3068\u306e\u5171\u50ac) \u65e5\u6642:\u00a0 \uff19\u6708\uff11\uff14\u65e5\uff08\u91d1\uff09 \uff11\uff15\uff1a\uff10\uff10 \u304b\u3089 \uff11\uff16\uff1a\uff13\uff10 \u5834\u6240:\u00a0 \u4eac\u5927 \u7406\u5b66\u7814\u7a76\u79d1 \u7269\u7406\u5b66\u6559\u5ba4(\u7406\uff15\u53f7\u9928)\u3000\uff14\uff10\uff11\u53f7\u5ba4 \u8b1b\u5e2b\uff1a Uri [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,50],"tags":[],"class_list":["post-1002","post","type-post","status-publish","format-standard","hentry","category-16","category-50"],"_links":{"self":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts\/1002","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\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1002"}],"version-history":[{"count":3,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts\/1002\/revisions"}],"predecessor-version":[{"id":1006,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=\/wp\/v2\/posts\/1002\/revisions\/1006"}],"wp:attachment":[{"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1002"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1002"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/kyoryu.scphys.kyoto-u.ac.jp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1002"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}