On the interaction between tides and convection
On the interaction between tides and convection
复制标题
潮汐与对流的相互作用
DOI：
10.1111/j.1365-2966.2012.20630.x
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发表时间：
2012
影响因子：
4.8
通讯作者：
G. Lesur
中科院分区：
文献类型：
--
作者：
G. Ogilvie;G. Lesur
本文通过分析均匀振荡切变对流体流动的影响，研究天体中潮汐与对流的相互作用。该模式可以用来描述大尺度周期性潮汐形变与小尺度对流运动之间的相互作用。我们首先考虑分析的限制，其中剪切是低振幅和振荡周期是短的时间尺度相比，未扰动流。在这个极限有一个粘弹性响应，我们得到的有效弹性模量和粘性系数的表达式。有效粘度与振荡频率的平方成反比，其系数可以是正的、负的或零，这取决于未扰动流的性质。我们还进行了直接数值模拟的Boussinesq对流在振荡剪切盒和测量随时间变化的雷诺应力。结果表明，湍流对流的有效粘度福尔斯迅速下降的振荡频率的增加，达到小的负值，在我们已经检查的情况下，虽然显着的不确定性仍然存在，因为湍流噪声。我们讨论了这种分析对天体物理潮汐的影响。
We study the interaction between tides and convection in astrophysical bodies by analysing the effect of a homogeneous oscillatory shear on a fluid flow. This model can be taken to represent the interaction between a large-scale periodic tidal deformation and a smaller scale convective motion. We first consider analytically the limit in which the shear is of low amplitude and the oscillation period is short compared to the time-scales of the unperturbed flow. In this limit there is a viscoelastic response and we obtain expressions for the effective elastic modulus and viscosity coefficient. The effective viscosity is inversely proportional to the square of the oscillation frequency, with a coefficient that can be positive, negative or zero depending on the properties of the unperturbed flow. We also carry out direct numerical simulations of Boussinesq convection in an oscillatory shearing box and measure the time-dependent Reynolds stress. The results indicate that the effective viscosity of turbulent convection falls rapidly as the oscillation frequency is increased, attaining small negative values in the cases we have examined, although significant uncertainties remain because of the turbulent noise. We discuss the implications of this analysis for astrophysical tides.