School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, Scotland, United Kingdom.
Phys Rev E. 2019 Jan;99(1-1):013101. doi: 10.1103/PhysRevE.99.013101.
We explore the effect of the magnetic Prandtl number Pm on energy and dissipation in fully resolved direct numerical simulations of steady-state, mechanically forced, homogeneous magnetohydrodynamic turbulence in the range 1/32<Pm<32. We compare the spectra and show that if the simulations are not fully resolved, the steepness of the scaling of the kinetic-to-magnetic dissipation ratio with Pm is overestimated. We also present results of decaying turbulence with helical and nonhelical magnetic fields, where we find nonhelical reverse spectral transfer for Pm<1. The results of this systematic analysis have applications including stars, planetary dynamos, and accretion disks.
我们探索了磁普朗特数 Pm 对稳态机械强迫均匀磁流体力学湍流的完全分辨直接数值模拟中能量和耗散的影响，范围为 1/32<Pm<32。我们比较了谱，并表明如果模拟没有完全分辨，那么动能到磁耗散比与 Pm 的标度陡度就会被高估。我们还给出了带有螺旋和非螺旋磁场的衰减湍流的结果，在那里我们发现 Pm<1 时非螺旋的反向谱传递。这种系统分析的结果包括恒星、行星发电机和吸积盘等应用。
