Vibratory control of heat transfer in fluid in containers with elastic boundaries*

An experimental study is carried on of heat transfer in a viscous fluid enclosed in cylindrical and spherical containers with vibrating elastic boundaries. The container boundary is thermally stabilized by pumping a liquid around it. Two cases are considered: the fluid bulk is heated while the boundary is cooled and the boundary is set at a constant higher temperature. Vibrations generate steady streaming in the container, intensifying the heat transfer. The former is studied using PIV method, the latter -- by evaluation of temperature difference between the fluids in the container and the thermostatic bath. The dimensionless velocity of steady flows increases with the pulsation Reynolds number, $Re_p$. The steady flows are in competition with the free convection. The domain of dimensionless parameters (Rayleigh number, $Ra$, and $Re_p$) where the free convection can be neglected is found. For this domain, the analysis of heat transfer by steady streaming as a function of the dimensionless vibration frequency is done. The obtained results can be applied for the assessment of flow structure and heat-mass transfer in oscillating elastic containers of various scale, for example liquid drops.