Following the recent discovery of new three-dimensional particle attractors driven by joint (fluid) thermovibrational and (particle) inertial effects in closed cavities with various shapes and symmetries [M. Lappa, Phys. Fluids 26(9), 093301 (2014); ibid. 31(7), 073303 (2019)], the present analysis continues this line of inquiry by probing influential factors hitherto not considered; among them, the role of the steady component of thermovibrational convection, i.e., the time-averaged velocity field that is developed by the fluid due to the non-linear nature of the overarching balance equations. It is shown how this apparently innocuous problem opens up a vast parameter space, which includes several variables, comprising (but not limited to) the frequency of vibrations, the so-called “Gershuni number,” the size of particles (Stokes number), and their relative density with respect to the surrounding fluid (density ratio). A variety of new particle structures (2D and 3D) are uncovered and a complete analysis of their morphology is presented. The results reveal an increase in the multiplicity of solutions brought in by the counter-intuitive triadic relationship among particle inertial effects and the instantaneous and time-averaged convective thermovibrational phenomena. Finally, a universal formula is provided that is able to predict correctly the time required for the formation of all the observed structures.

中文翻译：

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热振动驱动的粒子堆积结构中的对称破坏现象

最近在具有各种形状和对称性的封闭腔中发现了由关节（流体）热振动和（粒子）惯性效应驱动的新型三维粒子吸引子 [M. 拉帕，物理。流体 26(9), 093301 (2014)；同上。31(7), 073303 (2019)]，本分析通过探讨迄今未考虑的影响因素继续这一调查路线；其中，热振动对流稳定分量的作用，即由于总体平衡方程的非线性性质，由流体产生的时均速度场。展示了这个看似无害的问题如何打开一个巨大的参数空间，其中包括几个变量，包括（但不限于）振动频率、所谓的“格尔舒尼数”、粒子的大小（斯托克斯数）、以及它们相对于周围流体的相对密度（密度比）。发现了各种新的粒子结构（2D 和 3D），并提供了对其形态的完整分析。结果表明，粒子惯性效应与瞬时和时间平均对流热振动现象之间的反直觉三元关系带来了解决方案的多样性。最后，提供了一个通用公式，可以正确预测所有观察到的结构形成所需的时间。结果表明，粒子惯性效应与瞬时和时间平均对流热振动现象之间的反直觉三元关系带来了解决方案的多样性。最后，提供了一个通用公式，能够正确预测所有观察到的结构形成所需的时间。结果表明，粒子惯性效应与瞬时和时间平均对流热振动现象之间的反直觉三元关系带来了解决方案的多样性。最后，提供了一个通用公式，能够正确预测所有观察到的结构形成所需的时间。