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Director alignment at the nematicisotropic interface: elastic anisotropy and active anchoring
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences ( IF 5 ) Pub Date : 2021-08-30 , DOI: 10.1098/rsta.2020.0394
Rodrigo C V Coelho 1, 2 , Nuno A M Araújo 1, 2 , Margarida M Telo da Gama 1, 2
Affiliation  

Activity in nematics drives interfacial flows that lead to preferential alignment that is tangential or planar for extensile systems (pushers) and perpendicular or homeotropic for contractile ones (pullers). This alignment is known as active anchoring and has been reported for a number of systems and described using active nematic hydrodynamic theories. The latter are based on the one-elastic constant approximation, i.e. they assume elastic isotropy of the underlying passive nematic. Real nematics, however, have different elastic constants, which lead to interfacial anchoring. In this paper, we consider elastic anisotropy in multiphase and multicomponent hydrodynamic models of active nematics and investigate the competition between the interfacial alignment driven by the elastic anisotropy of the passive nematic and the active anchoring. We start by considering systems with translational invariance to analyse the alignment at flat interfaces and, then, consider two-dimensional systems and active nematic droplets. We investigate the competition of the two types of anchoring over a wide range of the other parameters that characterize the system. The results of the simulations reveal that the active anchoring dominates except at very low activities, when the interfaces are static. In addition, we found that the elastic anisotropy does not affect the dynamics but changes the active length that becomes anisotropic.

This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.



中文翻译:

向列各向同性界面处的导向对准:弹性各向异性和主动锚定

向列中的活动驱动界面流动,导致优先对齐,对于可拉伸系统(推动器)是切向或平面的,对于可收缩系统(拉器)是垂直或垂直的。这种对齐被称为主动锚定,并已针对许多系统进行了报道,并使用主动向列流体动力学理论进行了描述。后者基于单弹性常数近似,即它们假定底层被动向列的弹性各向同性。然而,真正的向列具有不同的弹性常数,这会导致界面锚定。在本文中,我们考虑了主动向列的多相和多组分流体动力学模型中的弹性各向异性,并研究了由被动向列的弹性各向异性驱动的界面排列与主动锚固之间的竞争。我们首先考虑具有平移不变性的系统来分析平面界面的对齐,然后考虑二维系统和活性向列液滴。我们研究了两种锚定在表征系统的广泛其他参数上的竞争。模拟结果表明,当界面是静态的时,主动锚定占主导地位,除非活动非常低。此外,我们发现弹性各向异性不会影响动力学,但会改变变为各向异性的活动长度。我们研究了两种锚定在表征系统的广泛其他参数上的竞争。模拟结果表明,当界面是静态的时,主动锚定占主导地位,除非活动非常低。此外,我们发现弹性各向异性不会影响动力学,但会改变变为各向异性的活动长度。我们研究了两种锚定在表征系统的广泛其他参数上的竞争。模拟结果表明,当界面是静态的时,主动锚定占主导地位,除非活动非常低。此外,我们发现弹性各向异性不会影响动力学,但会改变变为各向异性的活动长度。

本文是主题问题“流体动力学模拟中尺度方法的进展”的一部分。

更新日期:2021-08-30
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