ON THE VALIDITY CONDITIONS OF THE SATO HYPOTHESIS

Abstract

Many years ago, Sato and Sekoguchi proposed the additivity of inherent liquid turbulence and bubble-induced liquid pulsations (ordinarily pseudoturbulence) for two-phase bubbly flows. This hypothesis is often used in models of different two-phase flows and in the development of various flow codes, but the validity conditions of this hypothesis are not defined precisely. An electrodiffusional method involving eight double probes is used in this work to detect the wall shear stress in laminar and transitional upward two-phase bubble flows and check this hypothesis. Almost monodispersed spherical bubbles are used. The data show that for small bubbles the coupling of liquid turbulence and bubble pseudoturbulence can be more complex than the simple additivity proposed by Sato and Sekoguchi.