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_/ 流体力学セミナー ２００６ No. ８
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_/ 日 時 : ０６年 ９月 ４ 日 (月) １５：００〜１６：３０
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_/ 場 所 : 京大数理研 ００９号室
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_/ 講 師： Susan Kurien
_/ Los Alamos National Laboratory
_/ (Mathematical Modeling and Analysis group (T-7))
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_/ 題 目： Potential enstrophy cascades in rotating and stratified flows
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_/ 内 容 :
_/ The predicted $k^(-3)$ scaling of the 2D turbulence energy spectrum is
_/ governed by a direct enstrophy cascade (Kraichnan (1967)). This range
_/ is obtained in the limit as Reynold’s number goes to infinity in
_/ non-rotating, non-stratified flows. With the introduction of strong
_/ constant rate of rotation and stable, and strong stable
_/ stratification, in what is known as the quasi-geostrophic limit,
_/ Charney (1971) showed that an analogous behavior emerges for the total
_/ (kinetic plus potential) energy of the flow. He predicted a direct
_/ cascade of the so-called potential enstrophy with a corresponding
_/ scaling of $k^{-3}$ for the total energy spectrum.
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_/ Motivated by the Charney 1971 result for QG flows, we look at the
_/ dynamics of rotating and stratified flows with the aim of recovering,
_/ where possible, inertial range behavior in a wider range of parameter
_/ regimes of the flow. The main difference from the classical Kolmogorov
_/ approach is that we here look at potential enstrophy dynamics instead
_/ of energy dynamics. In contrast to Charney, we look at statistics in
_/ physical space instead of spectral. We discuss six different limits in
_/ the stratification (Froude number) and rotation (Rossby number) and
_/ show that at least three of these can give rise to possible “inertial
_/ ranges” for potential enstrophy. As a result, we offer new
_/ parameterizations of rotating and stratified flows. We discuss how
_/ some of these may have strong constraints on the energy spectrum
_/ similar to the QG/2D cases.
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世話人：松本 剛(京大理)、山田 道夫(京大数研)、藤 定義(京大理)、
アドバイザー：藤坂博一（京大情報学）、船越 満明（京大情報学）、
水島 二郎(同志社大工)、余田 成男（京大理）
連絡先：ohkitani@kurims.kyoto-u.ac.jp
メールリスト連絡先： semi-adm@kyoryu.scphys.kyoto-u.ac.jp
戻る [http://www.kyoryu.scphys.kyoto-u.ac.jp/semi/semi2.html]