论文标题
对流和内部重力波在其密度最大左右在4°C的密度周围激发
Coupled convection and internal gravity waves excited in water around its density maximum at 4°C
论文作者
论文摘要
耦合的混合对流和分层系统在天然流中很常见。为了实验研究相关的动力学，我们使用水的单数特性：其非线性状态方程的特征是最大密度接近$ 4^{\ circ} $ c。通过以$ 35^{\ circ} $ C加热油箱顶部，并以$ 0^{\ Circ} $ C冷却底部，出现了两层配置。底层中的对流运动主要由大规模循环和冷羽升起。这种湍流会在上部稳定分层的层中产生传播的内部重力波。进行PIV测量，并提出对流的光谱特征和内部重力波。观察到分层层中的水平大规模逆转流，该流程是由第三个中间层粘着的。该缓冲层位于对流层和分层层之间，并与对流的层热结合，因此维持强烈的水平剪切。具有几何学和物理参数接近实验的三维直接数值模拟证实了我们的实验结果。
Coupled mixed convective and stratified systems are common in natural flows. To study experimentally the associated dynamics, we use a singular property of water: its non-linear equation of state is characterised by a maximum density close to $4^{\circ}$C. By heating the top of a tank at $35^{\circ}$C and cooling the bottom at $0^{\circ}$C, a two-layer configuration spontaneously appears. The convective motion in the bottom layer consists mostly of a large-scale circulation and rising cold plumes. This turbulent flow generates propagating internal gravity waves in the upper stably-stratified layer. PIV measurements are performed and spectral characteristics of the convection and internal gravity waves are presented. An horizontal large-scale reversing flow in the stratified layer is observed which is viscously driven by a third, intermediate layer. This buffer layer is located between the convective and stratified layers and is thermally coupled with the convective one, hence sustaining a strong horizontal shear. Three dimensional direct numerical simulations with geometry and physical parameters close to the experimental ones corroborate our experimental results.
