Similarities between 2D and 3D convection for large Prandtl number
Similarities between 2D and 3D convection for large Prandtl number
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大普朗特数的 2D 和 3D 对流之间的相似之处
DOI：
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发表时间：
2014
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通讯作者：
Biplab Dutta
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作者：
Ambrish Pandey;M. Verma;A. Chatterjee;Biplab Dutta
利用直接数值模拟的瑞利-贝纳德对流（RBC），我们进行了比较研究的频谱和通量的能量和熵，以及大的和无限的普朗特数在二维（2D）和三维（3D）的大规模量的标度。我们观察到2D和3D RBC之间非常相似，特别是动能谱Eu（k）<$k−13/3，熵谱表现出一个以k−2谱为主的双分支。我们发现，在2D和3D流的主要傅立叶模式是非常接近的。因此，3D RBC是准二维的，这是2D和3D RBC对于大的和无限的普朗特数的相似性的原因。
Using direct numerical simulations of Rayleigh–Bénard convection (RBC), we perform a comparative study of the spectra and fluxes of energy and entropy, and the scaling of large-scale quantities for large and infinite Prandtl numbers in two (2D) and three (3D) dimensions. We observe close similarities between the 2D and 3D RBC, in particular, the kinetic energy spectrum Eu(k)∼k−13/3, and the entropy spectrum exhibits a dual branch with a dominant k−2 spectrum. We showed that the dominant Fourier modes in 2D and 3D flows are very close. Consequently, the 3D RBC is quasi-two-dimensional, which is the reason for the similarities between the 2D and 3D RBC for large and infinite Prandtl numbers.