论文标题
在强垂直磁场中湍流的雷利 - 贝纳德对流
Turbulent Rayleigh-Bénard convection in a strong vertical magnetic field
论文作者
论文摘要
进行直接的数值模拟，以研究具有轴向磁场的纵横比的圆柱形细胞中的湍流雷利 - 纳德对流中的流动结构和传输性能。考虑到prandtl编号为0.025，雷利和哈特曼的数字高达$ 10^9 $和1400。结果与早期实验和数值数据的结果一致。如预期的那样，强烈的磁场抑制了传热速率和动能。同时，发现他们在雷利数字中的增长速度更快，在Hartmann数字高。这种行为归因于新发现的流动状态，其特征是突出的准二维结构让人联想到磁流失动力湍流模拟中观察到的涡流板。在Chandrasekhar线性稳定性极限附近的流中发现了类似于旋转的旋转壁模式。报告了对流量的空间结构及其全球运输特性的影响的详细分析。
Direct numerical simulations are carried out to study flow structure and transport properties in turbulent Rayleigh-Bénard convection in a cylindrical cell of aspect ratio one with an imposed axial magnetic field. Flows at the Prandtl number 0.025 and the Rayleigh and Hartmann numbers up to $10^9$ and 1400 are considered. The results are consistent with those of earlier experimental and numerical data. As anticipated, the heat transfer rate and kinetic energy are suppressed by strong magnetic field. At the same time, their growth with the Rayleigh number is found to be faster in flows at high Hartmann numbers. This behaviour is attributed to the newly discovered flow regime characterized by prominent quasi two-dimensional structures reminiscent of vortex sheets observed earlier in simulations of magnetohydrodynamic turbulence. Rotating wall modes similar to those in the Rayleigh-Bénard convection with rotation are found in flows near the Chandrasekhar linear stability limit. Detailed analysis of the spatial structure of the flows and its effect of global transport properties is reported.
