9307723 Sangani The proposed research is to study in detail flows of bubbly liquids at large Reynolds number and of gas-solid suspensions at vanishing small Reynolds number and finite Stokes number. These flows are known to exhibit a number of distinct flow patterns depending upon flow rates and physical properties of the individual phases and the flow configuration. A combination of theoretical concepts of statistical mechanics and numerical simulations of the appropriate equations will be used to: (i) obtain a reliable set of averaged equations for describing these flows, including the closure and constitutive relations to be used in such equations; (ii) study the nonlinear growth of incipient instability of their uniform states leading to transitions to slug flows and bubbly fluidized beds; and (iii) search for mechanisms that stabilize the uniform state of bubbly liquids and gas-solid fluidized beds. The techniques to be developed for computing hydrodynamic interactions between bubbles and liquid, or between solid and gas, are expected toprovide the background for studying a variety of engineering problems that arise in industrial processes for dispersions and composites.
