Paul M R, Chiam K-H, Cross M C, Fischer P F
Department of Physics, California Institute of Technology 114-36, Pasadena 91125, USA.
Phys Rev Lett. 2004 Aug 6;93(6):064503. doi: 10.1103/PhysRevLett.93.064503. Epub 2004 Aug 4.
The coarsening and wave number selection of striped states growing from random initial conditions are studied in a nonrelaxational, spatially extended, and far-from-equilibrium system by performing large-scale numerical simulations of Rayleigh-Bénard convection in a large-aspect-ratio cylindrical domain with experimentally realistic boundaries. We find evidence that various measures of the coarsening dynamics scale in time with different power-law exponents, indicating that multiple length scales are required in describing the time dependent pattern evolution. The translational correlation length scales with time as t0.12, the orientational correlation length scales as t0.54, and the density of defects scale as t(-0.45). The final pattern evolves toward the wave number where isolated dislocations become motionless, suggesting a possible wave number selection mechanism for large-aspect-ratio convection.
通过在具有实验现实边界的大纵横比圆柱域中对瑞利 - 贝纳德对流进行大规模数值模拟，研究了从随机初始条件生长的条纹状态的粗化和波数选择，该系统是非弛豫的、空间扩展的且远离平衡的。我们发现有证据表明，粗化动力学的各种度量在时间上以不同的幂律指数缩放，这表明在描述随时间变化的图案演化时需要多个长度尺度。平移相关长度随时间按t^0.12缩放，取向相关长度按t^0.54缩放，缺陷密度按t^(-0.45)缩放。最终图案朝着孤立位错静止不动的波数演化，这为大纵横比对流提出了一种可能的波数选择机制。
