论文标题
湍流和热传递在旋转的,加热的半肥皂气泡上
Turbulence and heat transfer on a rotating, heated half soap bubble
论文作者
论文摘要
我们使用直接数值模拟来研究旋转的半肥皂气泡在其赤道加热的二维流动。加热产生浮力,旋转会在流体中产生科里奥利力。但是,由于气泡的弯曲表面,浮力和科里奥利力在气泡上随纬度而变化,从而产生了丰富的流动行为。我们首先探索流动的单点特性,包括雷诺和努塞尔特数字,平均场和雷诺的压力,都是纬度的函数。对于给定的瑞利数字,我们观察到对Rossby数量RO的非单调依赖性,并且大规模的平均循环受到旋转的强烈影响。然后,我们考虑揭示流动性质的数量,包括动能和热能的光谱和光谱通量以及速度和温度的结构功能。通量表明,仅用于平坦表面上的非构造二维湍流,在较大的尺度上有一个动能的高档通量(通过在较小的尺度下浮力的湍流动能注入湍流,在较小的尺度下的腹部下降磁通量。动能谱和速度结构函数在旋转效果较弱的尺度上很好地描述了Bolgiano-Obukhov(BO)缩放。但是,由于温度场的强烈间歇性,温度结构的功能通常不满意BO缩放。
We use Direct Numerical Simulations to study the two-dimensional flow of a rotating, half soap bubble that is heated at its equator. The heating produces buoyancy and rotation generates a Coriolis forces in the fluid. However, due to the curved surface of the bubble, the buoyancy and Coriolis forces vary with latitude on the bubble, giving rise to rich flow behavior. We first explore the single-point properties of the flow, including the Reynolds and Nusselt numbers, mean fields, and Reynolds stresses, all as a function of latitude. For a given Rayleigh number, we observe a non-monotonic dependence on the Rossby number Ro, and large scale mean circulations that are strongly influenced by rotation. We then consider quantities that reveal the multiscale nature of the flow, including spectrums and spectral fluxes of kinetic and thermal energy, and enstrophy, and structure functions of velocity and temperature. The fluxes show that just a for nonbuoyant two-dimensional turbulence on a flat surface, there is an upscale flux of kinetic energy at larger scales (fed by buoyancy injection of turbulent kinetic energy at smaller scales), and a downscale flux of enstrophy at smaller scales. The kinetic energy spectrum and velocity structure functions are well described by Bolgiano-Obukhov (BO) scaling at scales where the effects of rotation are weak. The temperature structure functions do not, however, satisfy BO scaling in general, due to strong intermittency in the temperature field.