Institut Langevin, Ecole Supérieure de Physique et de Chimie Industrielles de Paris, Université Paris Sciences et Lettres, CNRS, Paris F-75005, France.
Laboratoire de Physique et Mécanique des Milieux Hétérogènes, Ecole Supérieure de Physique et de Chimie Industrielles de Paris, CNRS, Université Paris Sciences et Lettres, Sorbonne Université, Université de Paris, Paris F-75005, France.
Proc Natl Acad Sci U S A. 2021 Nov 30;118(48). doi: 10.1073/pnas.2111214118.
Gravity shapes liquids and plays a crucial role in their internal balance. Creating new equilibrium configurations irrespective of the presence of a gravitational field is challenging with applications on Earth as well as in zero-gravity environments. Vibrations are known to alter the shape of liquid interfaces and also to change internal dynamics and stability in depth. Here, we show that vibrations can also create an "artificial gravity" in any direction. We demonstrate that a liquid can maintain an inclined interface when shaken in an arbitrary direction. A necessary condition for the equilibrium to occur is the existence of a velocity gradient determined by dynamical boundary conditions. However, the no-slip boundary condition and incompressibility can perturb the required velocity profile, leading to a destabilization of the equilibrium. We show that liquid layers provide a solution, and liquid walls of several centimeters in height can thus be stabilized. We show that the buoyancy equilibrium is not affected by the forcing.
重力塑造了液体的形态，并在其内部平衡中起着至关重要的作用。在地球上和零重力环境中，创造新的平衡构型而不考虑重力场的存在具有挑战性。振动已知会改变液体界面的形状，并且还会改变深度处的内部动力学和稳定性。在这里，我们表明振动也可以在任何方向上产生“人工重力”。我们证明，当液体在任意方向上振动时，液体可以保持倾斜的界面。发生平衡的必要条件是存在由动力学边界条件确定的速度梯度。然而，无滑移边界条件和不可压缩性会干扰所需的速度分布，从而导致平衡失稳。我们表明，液体层提供了一种解决方案，因此几厘米高的液体壁可以得到稳定。我们表明浮力平衡不受外力的影响。
