Dependence of convective boundary mixing on boundary properties and turbulence strength
Dependence of convective boundary mixing on boundary properties and turbulence strength
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对流边界混合对边界特性和湍流强度的依赖性
DOI：
10.1093/mnras/stz312
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发表时间：
2019
影响因子：
4.8
通讯作者：
Cristini A
中科院分区：
文献类型：
--
作者：
Cristini A
对流边界混合是恒星演化中的主要不确定性之一。为了研究其依赖于边界性质和湍流强度的控制方式，我们计算了一系列的三维流体动力学模拟恒星对流碳燃烧过程中的驱动光度的不同的助推因子。我们的三维隐式大涡模拟是用prompicode计算的。我们进行了一个平均场分析的模拟内的平均Navier-Stokes框架。对流区内的垂直均方根速度和边界的体理查森数都与理论预期的驱动光度成比例：分别为1/3和RiB <$L−2/3。对流边界的位置估计，通过组合物剖面横跨它们，对流边界混合的强度是通过分析夹带法的框架内的边界。我们发现，夹带是近似成反比的散装理查森数，RiB（）。虽然夹带法不包括所有的过程发生在边界处，我们的研究结果支持使用夹带法来描述对流边界混合在一维模型中，至少对于先进的阶段。还讨论了今后的步骤和挑战。
Convective boundary mixing is one of the major uncertainties in stellar evolution. In order to study its dependence on boundary properties and turbulence strength in a controlled way, we computed a series of 3D hydrodynamical simulations of stellar convection during carbon burning with a varying boosting factor of the driving luminosity. Our 3D implicit large eddy simulations were computed with theprompicode. We performed a mean field analysis of the simulations within the Reynolds-averaged Navier–Stokes framework. Both the vertical rms velocity within the convective region and the bulk Richardson number of the boundaries are found to scale with the driving luminosity as expected from theory:∝L1/3and RiB∝L−2/3, respectively. The positions of the convective boundaries were estimated through the composition profiles across them, and the strength of convective boundary mixing was determined by analysing the boundaries within the framework of the entrainment law. We find that the entrainment is approximately inversely proportional to the bulk Richardson number, RiB(). Although the entrainment law does not encompass all the processes occurring at boundaries, our results support the use of the entrainment law to describe convective boundary mixing in 1D models, at least for the advanced phases. The next steps and challenges ahead are also discussed.
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DOI：
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发表时间：
2017
期刊：
影响因子：
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DOI：
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DOI：
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发表时间：
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期刊：
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影响因子：
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影响因子：
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