论文标题
在不及时分层的大气边界层中的沙尘暴的无关模型研究
An inviscid model study of sandstorm in unstably stratified atmospheric boundary layer
论文作者
论文摘要
根据现场观测，大气边界层通常在灰尘和沙尘暴之前不稳定地分层，这是具有极高雷诺数的颗粒湍流重力电流。在本文中，建立了一个无粘性模型，以研究控制重力电流的俯冲阶段的机制，并且显示出无量纲的前速度（Froude）数量时，当电流流体或环境培养基或两种流体被不稳定地分层时，会降低。尽管密度界面混合，但直接模型所描述的前速与前速之间的关系与数值模拟结果一致，其中计算出不同初始锁定高度的锁定锁定重力电流针对不同的不稳定分层案例计算。此外，通过在沙尘暴方面通过现场观测获得的速度增量与模型的评估令人满意，这表明Inviscid机制为如此高的雷诺数数量湍流提供了贡献。
According to field observations, the atmospheric boundary layer is usually unstably stratified before a dust and sandstorm, the particle-laden turbulent gravity current with an extremely high Reynolds number. In this paper, an inviscid model is built to study the mechanism governing the slumping phase of gravity current, and it is shown that the dimensionless current front speed, the Froude number, decreases when the current fluid or the ambient medium or both fluids are unstably stratified. In spite of the density interface mixing, the relation between the front speed and the front height described by the inviscid model agrees with the numerical simulation results, where the lock-exchange gravity currents with different initial lock heights are calculated for different unstable stratification cases. Furthermore, the velocity increments obtained by field observations at the sandstorm fronts are satisfactorily consistent with the evaluations of the model, suggesting that the inviscid mechanism makes contribution to such high Reynolds number turbulent flows.
