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Dispersed-Phase Stress Tensor In Flows Of Bubbly Liquids At Large Reynolds Numbers, Ashok S. Sangani, A. K. Didwania
Dispersed-Phase Stress Tensor In Flows Of Bubbly Liquids At Large Reynolds Numbers, Ashok S. Sangani, A. K. Didwania
Ashok S. Sangani
We derive averaged equations for large Reynolds number laminar flows of gas–liquid dispersions accounting for slowly varying spatial and temporal fields. In particular, we obtain an exact expression for the dispersed-phase stress tensor to be used in the force balance equation for gas bubbles and illustrate its application by evaluating the stress tensor for a few special cases. It is shown that the dispersed-phase stress tensor gradient with respect to the mean relative motion or the void fraction for the uniformly random bubbly liquids under conditions of large Reynolds number laminar flows is negative and thus has a destabilizing influence …
Linear Acoustic Properties Of Bubbly Liquids Near The Natural Frequency Of The Bubbles Using Numerical Simulations, Ashok S. Sangani, R. Sureshkumar
Linear Acoustic Properties Of Bubbly Liquids Near The Natural Frequency Of The Bubbles Using Numerical Simulations, Ashok S. Sangani, R. Sureshkumar
Ashok S. Sangani
We consider the problem of determining linear acoustic properties of bubbly liquids near the natural frequency of the bubbles. Since the effective wavelength and attenuation length are of the same order of magnitude as the size of the bubbles, we devise a numerical scheme to determine these quantities by solving exactly the multiple scattering problem among many interacting bubbles. It is shown that the phase speed and attenuation are finite at natural frequency even in the absence of damping due to viscous, thermal, nonlinear, and liquid compressibility effects, thus validating a recent theory (Sangani 1991). The results from the numerical …
Dynamic Simulations Of Flows Of Bubbly Liquids At Large Reynolds Numbers, Ashok S. Sangani, A. K. Didwania
Dynamic Simulations Of Flows Of Bubbly Liquids At Large Reynolds Numbers, Ashok S. Sangani, A. K. Didwania
Ashok S. Sangani
Results of dynamic simulations of bubbles rising through a liquid are presented. The Reynolds number of the flow based on the radius and the terminal speed of bubbles is large compared to unity, and the Weber number, which is the ratio of inertial to surface tension forces, is small. It is assumed that the bubbles do not coalesce when they approach each other but rather bounce instantaneously, conserving the momentum and the kinetic energy of the system. The flow of the liquid is assumed to be irrotational and is determined by solving the many-bubble interaction problem exactly. The viscous force …