THEORY AND SIMULATIONS OF ROTATING CONVECTION
THEORY AND SIMULATIONS OF ROTATING CONVECTION
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DOI：
10.1088/0004-637x/791/1/13
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发表时间：
2014-08-10
影响因子：
4.9
通讯作者：
Lithwick, Yoram
中科院分区：
文献类型：
--
作者：
Barker, Adrian J.;Dempsey, Adam M.;Lithwick, Yoram
我们研究旋转流体中的热对流，以更好地理解旋转恒星和行星中对流区的性质。我们首先推导出一个快速旋转对流的混合长度理论，通过简单的物理论证得出史蒂文森的结果。该理论预测的对流作为施加的热通量和旋转速率的函数，独立的微观扩散系数的属性。特别是，它预测的平均温度梯度，均方根速度和温度波动，以及主导热传输的涡流的大小。我们测试所有这些预测与高分辨率的三维Boussinesq对流在笛卡尔框流体动力学模拟。在两个数量级以上的转速范围内，计算结果与理论计算结果吻合得非常好。例如，温度梯度被预测为在固定通量下旋转速率的五分之四次幂，并且模拟产生0.75 +/- 0.06。我们的结论是混合长度理论是一个坚实的基础，了解在旋转的恒星和行星的对流区的性质。
We study thermal convection in a rotating fluid in order to better understand the properties of convection zones in rotating stars and planets. We first derive a mixing-length theory for rapidly rotating convection, arriving at the results of Stevenson via simple physical arguments. The theory predicts the properties of convection as a function of the imposed heat flux and rotation rate, independent of microscopic diffusivities. In particular, it predicts the mean temperature gradient, the rms velocity and temperature fluctuations, and the size of the eddies that dominate heat transport. We test all of these predictions with high resolution three-dimensional hydrodynamical simulations of Boussinesq convection in a Cartesian box. The results agree remarkably well with the theory across more than two orders of magnitude in rotation rate. For example, the temperature gradient is predicted to scale as the rotation rate to the four-fifths power at fixed flux, and the simulations yield 0.75 +/- 0.06. We conclude that the mixing-length theory is a solid foundation for understanding the properties of convection zones in rotating stars and planets.