Onset of thermal convection and its flow patterns in a rectangular cavity
Onset of thermal convection and its flow patterns in a rectangular cavity
复制标题
矩形腔内热对流的开始及其流动模式
DOI：
10.1088/0169-5983/47/6/065505
复制
发表时间：
2015
影响因子：
1.5
通讯作者：
Y. Fukazawa and M. Funakoshi
中科院分区：
文献类型：
--
作者：
山崎 徳幸，船越 満明;A.Hiramitsu and M.Funakoshi;Y. Fukazawa and M. Funakoshi
假设腔壁为刚性，且具有理想的导热性，研究了在纵横比为Ax和Ay的矩形腔体中，流体在垂直线性温度场作用下的热对流的发生。当Ax和Ay小于6时，用高精度的Galerkin谱方法计算了临界Rayleigh数Rc和大多数不稳定模态的定常流型。流型的特点进行了检查，通过使用上壁流模式的基础上近壁速度场，垂直速度分布，和流体颗粒的轨迹。我们发现，一个对称模式，是不是最不稳定时，Ax和Ay之间的差异是大的，是最不稳定的，如果Ax和Ay都在4或5.5左右。该模式的流动模式与先前的实验研究结果是一致的。Rc随Ax或Ay的减小而迅速增大，随Ax或Ay的增大而缓慢减小。有限滚转假设的有效性被发现是有限的，即使Ax和Ay之间的差异是大的。流动模式为
The onset of thermal convection of a fluid in a rectangular cavity of aspect ratios A x and A y exposed to a vertically linear temperature field is examined under the assumption that all its walls are rigid, and of perfect thermal conductance. For several A x and A y smaller than 6, the critical Rayleigh number R c and the steady flow patterns of most unstable modes are computed by a Galerkin spectral method of high accuracy. Characteristics of flow patterns are examined by using upper-wall flow patterns based on near-wall velocity fields, distributions of vertical velocity, and trajectories of fluid particles. We find that a symmetry mode that is not the most unstable when the difference between A x and A y is large is the most unstable if both A x and A y are around 4 or around 5.5. The flow pattern of this mode is consistent with the results in a preceding experimental study. R c increases rapidly as A x or A y decreases to zero and decreases slowly as they increase. The validity of the assumption of finite roll is found to be limited, even if the difference between A x and A y is large. The flow pattern for