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Research Abstracts Online
January 2010 - March 2011

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University of Minnesota Twin Cities
College of Science and Engineering
Department of Aerospace Engineering and Mechanics

PI: Daniel D. Joseph, Fellow

Direct Numerical Simulation and Modeling of Multiphase Flows

The theories of viscous potential flow (VPF) and dissipation method (DM) have been applied to the study of different problems in two-phase fluid dynamics. The VPF approach assumes irrotational fluid motion considering viscous stresses in the normal stress balance across fluid-fluid interfaces. DM stems from the integration of the mechanical energy equation assuming irrotational motion except that continuity of tangential stress and velocity is enforced at gas-liquid and liquid-liquid interfaces. This group has carried out the numerical analysis of the deformation and break-up time of a bubble or drop in a uniaxial straining flow by means of VPF using the direct formulation of the boundary-element method (BEM) coupled with a time-integration routine to advance the surface in time. The results for the bubble break-up time from VPF are compared with numerical results from the incompressible Navier-Stokes equations recently published. It is found that for the interval of Weber numbers, 3 ≤ We ≤ 6, both theories show agreement. The developed code may be applied to the investigation of nonlinear deformations in other physical setups. In addition, these researchers have conducted the study of moving thin film rupture as a consequence of van der Waals forces using linear stability analysis and the concept of disjoining pressure. Linear stability analyses have also been carried out to study the break-up of a suddenly accelerating viscous drop, and for the case of Kelvin-Helmholtz instability including viscous effects via purely irrotational theories or a coupled rotational-irrotational theory.

Another interest of this group over a number of years has been the investigation of the fundamental dynamics of three-dimensional motions of solid particles in Newtonian and viscoelastic fluids. In the past, the researchers have developed two separate scalable and highly efficient parallel finite-element codes, the arbitrary Lagrangian-Eulerian particle mover and the disordered local movement particle mover. This research focused on the migration of particles in three-dimensional pressure-driven flows and the development of explicit formulas for the lift forces on the particles by correlating data from direct numerical simulation.

Group Members

Runyuan Bai, Research Associate
Ben Colcord, Collaborator
Roland Glowinski, Department of Mathematics, University of Houston, Houston, Texas
Todd Hesla, Collaborator
Hyungjun Kim, Research Associate
Juan Carlos Padrino, Research Associate
Reza Ramazani-Rend, Graduate Student
Flavia Viana, Collaborator
Jing Wang, Collaborator
Haoping Yang, Collaborator