Instituto Nacional de Matemática Pura e Aplicada-IMPA, 22460-320 Rio de Janeiro, Brazil.
Phys Rev Lett. 2018 Aug 10;121(6):064501. doi: 10.1103/PhysRevLett.121.064501.
The dispute on whether the three-dimensional (3D) incompressible Euler equations develop an infinitely large vorticity in a finite time (blowup) keeps increasing due to ambiguous results from state-of-the-art direct numerical simulations (DNS), while the available simplified models fail to explain the intrinsic complexity and variety of observed structures. Here, we propose a new model formally identical to the Euler equations, by imitating the calculus on a 3D logarithmic lattice. This model clarifies the present controversy at the scales of existing DNS and provides the unambiguous evidence of the following transition to the blowup, explained as a chaotic attractor in a renormalized system. The chaotic attractor spans over the anomalously large six-decade interval of spatial scales. For the original Euler system, our results suggest that the existing DNS strategies at the resolution accessible now (and presumably rather long into the future) are unsuitable, by far, for the blowup analysis, and establish new fundamental requirements for the approach to this long-standing problem.
由于最先进的直接数值模拟 (DNS) 结果存在歧义,关于三维(3D)不可压缩 Euler 方程是否会在有限时间内产生无限大的涡度(blowup)的争议不断增加,而现有的简化模型未能解释所观察到的结构的内在复杂性和多样性。在这里,我们通过模仿 3D 对数晶格上的微积分,提出了一个与 Euler 方程形式完全相同的新模型。该模型澄清了现有 DNS 尺度上的当前争议,并提供了向 blowup 过渡的明确证据,解释为重整化系统中的混沌吸引子。混沌吸引子跨越了异常大的六十年空间尺度间隔。对于原始 Euler 系统,我们的结果表明,目前(可能在相当长的未来)可访问的分辨率的现有 DNS 策略远远不适合 blowup 分析,并为解决这个长期存在的问题建立了新的基本要求。