论文标题
在墙壁绑定的指法双重扩散对流的模型上
On the wall-bounded model of fingering double diffusive convection
论文作者
论文摘要
通过二维直接数值模拟对壁挂式结构域进行了使用真实海水特性的指法双扩散对流，并与完全周期域的结果进行了比较。对于两个水平板之间固定的不稳定盐度差，随着稳定的温度差异的增加，对流的流量结构从对流卷转换为盐指。同时，由平均标量梯度计算得出的大量密度比超过了统一。当散装热雷数（由散装和域高度的平均温度梯度定义）大于$ 10^7 $时，盐指的特征高度远小于域高度，流量进入了自由盐指状态。在此制度中，传输性能与在完全周期域中获得的传输性能一致（例如Traxler等人J.流体机械，677，530-553，2011）。盐指的散装不会自发地闯入多层楼梯，这可能是由于固体边界阻止了大规模二级不稳定性的发展。对于此处考虑的最高盐度瑞利数字的密度比的有限范围，多层状态是从具有均匀盐度分布和垂直线性温度分布的初始条件直接确定的。
Fingering double diffusive convection with real seawater properties is studied by two-dimensional direct numerical simulations for the wall-bounded domain and compared with the results for fully periodic domain. For fixed unstable salinity difference between two horizontal plates, dominant flow structures change from convection rolls to salt fingers as the stable temperature difference increases. Meanwhile the bulk density ratio calculated by the mean scalar gradients exceeds unity. When the bulk thermal Rayleigh number, which is defined by the mean temperature gradient in the bulk and the domain height, is larger than $10^7$, the characteristic height of salt fingers is much smaller than the domain height and the flow enters the free salt-finger regime. In this regime the transport properties agree quantitatively with those obtained in the fully periodic domain (e.g. Traxler et al. J. Fluid Mech., 677, 530-553, 2011). The salt-finger bulk does not spontaneously break into multi-layer staircases probably due to the fact that solid boundary prevents the development of large-scale secondary instabilities. For the limited range of density ratio at the highest salinity Rayleigh number considered here, the multi-layer state is directly established from the initial condition with uniform salinity distribution and vertically linear temperature distribution.
