DIRECT NUMERICAL SIMULATIONS OF MULTIPHASE FLOWS

INTRODUCTIONMultiphase and multifluid flows are commonin many natural and technologically importantprocesses. Rain,spray combustion,spray paint-ing,and boiling heat transfer are just a few ex-amples.While it is the overall,integral charac-teristics of such flows that are of most interest,the global behavior is determined to a large de-gree by the evolution of the smallestscales in theflow.The combustion of sprays,for example,depends on the size and the number density ofthe drops.Generally…

DIRECT NUMERICAL SIMULATIONS OF MULTIPHASE FLOWS

Direct numerical simulations have recently emerged as a viable tool to study finite Reynolds number multiphase flows. The approach parallels direct numerical simulations of turbulent flows, but the unsteady motion of a deformable phase boundary adds considerable complexity. Here, a front tracking method that has been used to study several multiphase flow problems is described. The Navier Stokes equations are solved by a finite difference/front tracking technique that allows the inclusion of fully deformable interfaces and surface tension, in addition to inertial and viscous effects. A parallel version of the method makes it possible to use large grids and resolve flows containing a few hundred bubbles.