二维矩形腔体中混合流体行进波对流

Rayleigh-Benard模型是研究对流稳定性,时空结构和非线性特性的典型模型之一。本文的兴趣集中在二维矩形腔体中混合流体对流场的结构方面。利用SIMPLE算法数值求解流体力学方程组,模拟了充分发展的二维矩形腔体中混合流体对流。结果说明偏离传导失去稳定的系统经过亚临界分叉产生了振动对流。进一步,我们给出了分叉曲线及其沿分叉曲线的上部分支三个Rayleigh数对应的对流图案的垂直速度场,流线,温度场,浓度场和Shadowgraph强度的等值线图。所有场的结构分析表明浓度场及Shadowgraph强度的等值线图可以很好的特征行进波的运动特性。

Traveling Wave Convection for Binary Fluid Mixtures in Two Dimensional Rectangular Cell

Rayleigh-Benard model is one of the typical models for studying the stability,spatio temporal structure and nonlinear dynamics of convection.Our interests focus on the structures of convection fields for binary fluid mixtures in two dimensional rectangular cell.Using SIMPLE method,the simulations of fully developed convection for binary fluid mixtures in two dimensional rectangular cell was provided by numerically solving the hydrodynamic equations.The results show that the system which loses stability from a thermal conductive state gives an oscillating convective state via a subcritical bifurcation. Further,the bifurcation diagram and the contour maps of vertical velocity field,streamlines,temperature field,concentration field and sideview shadowgraph intensities corresponding to the convection patterns of three Rayleigh numbers along the bifurcation upper branch were given.The detailed structural analysis of all fields indicates that the motion property of traveling wave can well be characterized by the contour maps of concentration field and sideview shadowgraph intensities.