Dynamics of Two-liquid System at Rotation and Vibration with Equal Frequencies
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ORIGINAL ARTICLE
Dynamics of Two-liquid System at Rotation and Vibration with Equal Frequencies Ivan Karpunin1 · Nikolai Kozlov1 Received: 16 April 2020 / Accepted: 18 August 2020 © Springer Nature B.V. 2020
Abstract The impact of vibrations on the dynamics of a system of two immiscible liquids filling a rotating container is studied experimentally. A horizontal cylindrical container is rotating at a rate sufficient for the liquids, whose densities are not equal, to become steadily distributed in the form of core and annulus. The vibrational motion of the container has a frequency virtually equal to that of rotation. It is demonstrated that at the coincidence of the frequencies the container’s oscillations lead to the transformation of the centrifugal field. As a result, the column of light liquid is shifted steadily in the rotating frame of reference. With the increase in the amplitude of vibrational forcing, in a threshold manner the liquid–liquid interface loses its axial symmetry, and a centrifugal wave emerges on it. The threshold of wave onset is determined by the dimensionless vibrational acceleration. The obtained results demonstrate a possibility to apply vibrations for the positioning of a liquid core in a rotating container and for the control of its dynamics. Keywords Rotation · Vibration · Liquid–liquid interface · Waves
Introduction Rotating systems are an actually important topic for microgravity conditions: since the concept of a rotating space station, where the centrifugal force is used for creating artificial gravity, to the numerous applications in modern research and technology. For example, a passive cyclonic phase separator is proposed for the optimization of water recycling in space (Hoyt et al. 2013; Wu et al. 2017). Rotating-wall vessels are applied to simulate the microgravity effect on the living forms (Li et al. 2017). Rotating systems with a core and a spherical shell are studied in problems related to the fluid dynamics of planetary-type systems (Kozlov et al. 2019; Zaussinger et al. 2019). The research was supported by the Russian Science Foundation (project 18-71-10053). Nikolai Kozlov
[email protected] Ivan Karpunin [email protected] 1
Vibrational Hydromechanics Laboratory, Perm Humanitarian-Pedagogical University, Perm, Russia
State
At rotation, hydrodynamic systems acquire some nontrivial properties due to the action of inertia forces: centrifugal and Coriolis (Greenspan 1968). In this case the centrifugal force creates an additional radial force field and plays the stabilizing role for fluid motion. In particular, such systems may have a sound response to some particular frequencies of external mechanical excitation. This makes vibrations a prominent tool for the manipulation of rotating fluid systems in microgravity. In particular, a strong effect on multiphase systems may be expected due to an inhomogeneous density distribution. In this context, the knowledge about the effects of oscillation on rotating multiphase systems turns to be important for space industries.
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