دورية أكاديمية
Physical mechanism of the inverse energy cascade of two-dimensional turbulence: a numerical investigation
| العنوان: | Physical mechanism of the inverse energy cascade of two-dimensional turbulence: a numerical investigation |
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| المؤلفون: | Xiao, Z., Wan, M., Chen, S., Eyink, G. L. |
| المساهمون: | Xiao, Z (reprint author), Peking Univ, Coll Engn, Beijing 100871, Peoples R China., Peking Univ, State Key Lab Turbulence & Complex Syst, Beijing 100871, Peoples R China., Johns Hopkins Univ, Dept Mech Engn, Baltimore, MD 21218 USA., Johns Hopkins Univ, Dept Appl Math & Stat, Baltimore, MD 21218 USA., Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA., Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA., Peking Univ, Coll Engn, Beijing 100871, Peoples R China. |
| المصدر: | EI ; SCI |
| بيانات النشر: | journal of fluid mechanics |
| سنة النشر: | 2009 |
| المجموعة: | Peking University Institutional Repository (PKU IR) / 北京大学机构知识库 |
| مصطلحات موضوعية: | TWO-DIMENSIONAL TURBULENCE, GEOSTROPHIC TURBULENCE, ISOTROPIC TURBULENCE, INERTIAL-RANGE, HOMOGENEOUS TURBULENCE, ENSTROPHY TRANSFER, ELLIPTIC VORTEX, BETA-PLANE, SCALE, SIMULATION |
| الوصف: | We report an investigation or inverse energy cascade in steady-state two-dimensional turbulence by direct numerical simulation (DNS) of the two-dimensional Navier-Stokes equation, with small-scale forcing and large-scale damping. We employed several types of damping and dissipation mechanisms in simulations up to 2048(2) resolution. For all these simulations we obtained a wavenumber range for which the mean spectral energy flux is a negative constant and the energy spectrum scales as k (5/3), consistent with the predictions of Kraichnan (Phys. Fluids, vol. 439, 1967, p. 1417). To gain further insight, we investigated the energy cascade in physical space, employing a local energy flux defined by smooth filtering. We found that the inverse energy cascade is scale local, but that the strongly local contribution vanishes identically, as argued by Kraichnan (J. Fluid Mech., vol. 47, 1971, p. 525). The mean flux across a length scale l was shown to be due mainly to interactions with modes two to eight times smaller. A major part of our investigation was devoted to identifying the physical mechanism of the two-dimensional inverse energy cascade. One popular idea is that inverse energy cascade proceeds via merger of like-sign vortices. We made a quantitative study employing a precise topological criterion of merger events. Our statistical analysis showed that vortex mergers play a negligible direct role in producing mean inverse energy flux in our simulations. Instead, we obtained with the help of other works considerable evidence in favour of a 'vortex thinning' mechanism, according to which the large-scale strains do negative work against turbulent stress as they stretch out the isolines of small-scale vorticity. In particular, we studied a multi-scale gradient (MSG) expansion developed by Eyink (J. Fluid Mech., vol. 549, 2006a, p. 159) for the turbulent stress, whose contributions to inverse cascade call all be explained by 'thinning'. The MSG expansion up to second order ill space gradients was found to predict well ... |
| نوع الوثيقة: | journal/newspaper |
| اللغة: | English |
| تدمد: | 0022-1120 |
| العلاقة: | JOURNAL OF FLUID MECHANICS.2009,619,1-44.; 941221; http://hdl.handle.net/20.500.11897/316114Test; WOS:000263528900001 |
| DOI: | 10.1017/S0022112008004266 |
| الإتاحة: | https://doi.org/20.500.11897/316114Test https://doi.org/10.1017/S0022112008004266Test https://hdl.handle.net/20.500.11897/316114Test |
| رقم الانضمام: | edsbas.F6CB9950 |
| قاعدة البيانات: | BASE |
| تدمد: | 00221120 |
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| DOI: | 10.1017/S0022112008004266 |