ISSN Online: 2377-424X
International Heat Transfer Conference 12
Dynamics of a bump of the gas-liquid interface on which a submerged liquid jet impinges
要約
A quake motion of a liquid bump formed due to a submerged liquid jet impinging on a gas-liquid interface was analyzed
from a viewpoint of the surface-renewal effect on interphase heat/mass transfer. Sequential video images of a liquid bump
were processed to evaluate dynamics of the liquid bump quaking not only vertically but also transversely. Velocity fluctuations were also measured within the liquid bump as well as beneath the interface. The height and width (diameter) of
the bump were correlated with the nozzle-to-interface distance and the jet Reynolds number. When the nozzle-to-interface
distance was smaller than seven nozzle diameters, two characteristic frequencies of swelling and fluttering oscillations were determined definitely by a spectral analysis. When the nozzle-to-interface distance was larger than seven nozzle diameters, a characteristic time scale was also determined definitely by a wavelet analysis with the aid of logarithmic expectation. It has been concluded that the characteristic frequency of surface renewalmotion comes from the phase velocity andwavelength of the large-scale coherent structures convected downstream in the shear layer of an approach jet.