Influence of High Frequency Vertical Vibrations on Convective Regimes in a Closed Cavity at Normal and Low Gravity Conditions

摘要

The influence of high-frequency vibrations on the convection of a liquid in an infinitely long horizontal cylinder of square cross-section, which undergoes vertical vibrations, is investigated. The problem was solved numerically on the basis of the averaged equations of thermal vibrational convection, written in terms of the vorticity of the average velocity and stream functions of the average and pulsating flows. The influence of vibrations on the system was determined by a dimensionless vibration parameter V proportional to the ratio of vibrational acceleration to gravitational acceleration and independent of the temperature difference. The values V = 1 correspond to the case of low gravity conditions. The intensity of gravitational convection was characterized by the Grashof number Gr. All calculations were performed for the fixed value of the Prandtl number Pr = 100. For values 0 = V = 10 the evolution of average convective regimes was studied and a map of these regimes was plotted on the Gr-V parameter plane. The stability boundary of stationary average convection is determined. It is shown that after the loss of stability by a stationary average flow in a cavity, two oscillatory average convective regimes with different symmetries can be realized.