Libration-Generated Average Convection in a Rotating Flat Layer with Horizontal Axis
Kirill Rysin*
Laboratory of Vibrational Hydromechanics, Perm State Humanitarian Pedagogical University, Perm, 614990, Russia
*
Corresponding Author: Kirill Rysin. Email: rysin@pspu.ru
(This article belongs to the Special Issue: Advanced Problems in Fluid Mechanics)
Fluid Dynamics & Materials Processing https://doi.org/10.32604/fdmp.2024.052324
Received 30 March 2024; Accepted 06 June 2024; Published online 25 June 2024
Abstract
The study of average convection in a rotating cavity subjected to modulated rotation is an interesting area for the
development of both fundamental and applied science. This phenomenon finds application in the field of mass
transfer and fluid flow control, relevant examples being crystal growth under reduced gravity and fluid mixing in
microfluidic devices for cell cultures. In this study, the averaged flow generated by the oscillating motion of a fluid
in a planar layer rotating about a horizontal axis is experimentally investigated. The boundaries of the layer are
maintained at constant temperatures, while the lateral cylindrical wall is thermally insulated. It is demonstrated
that libration results in intense oscillatory fluid motion, which in turn produces a time-averaged flow. For the first
time, quantitative measures for the instantaneous velocity field are obtained using the Particle Image Velocimetry
technique. It is revealed that the flow has the form of counter-rotating vortices. The vortex circulations sense
changes during a libration cycle. An increase in the rotation rate and amplitude of the cavity libration results
in an increase in the flow intensity. The heat transfer and time-averaged velocity are examined accordingly as
a function of the dimensionless oscillation frequency, and resonant excitation of heat transfer and average oscillation velocity are revealed. The threshold curve for the onset of the averaged convection is identified in the plane of
control parameters (dimensionless rotational velocity and pulsation Reynolds number). It is found that an
increase in the dimensionless rotational velocity has a stabilizing effect on the onset of convection.
Keywords
Rotation; libration; oscillations; mass transfer; stability; averaged convection
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