## Research Abstracts Online

January
2008 - March 2009

### University of Minnesota Twin Cities

Institute of Technology

Department of Aerospace Engineering and Mechanics

## PI: Daniel D. Joseph, Fellow

### Direct Numerical Simulation and Modeling of Multiphase Flows

This group is applying the approaches of viscous potential flow (VPF) and dissipation method (DM) 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 velocity and stress is assumed at gas-liquid and liquid-liquid interfaces. The group has applied the strategy of VPF in the analysis of stress-induced cavitation for axisymmetric flow past a sphere. VPF and DM analyses have been performed to model the decay rate of oscillations and standing waves in spherical drops and bubbles as well as in the case of capillary-gravity waves on a plane surface. VPF is also applied to model the nonlinear behavior of drops and bubbles using boundary-integral methods.

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. 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

Roland Glowinski, Department of Mathematics, University of Houston, Houston, Texas

Todd Hesla, Research Associate

Juan Carlos Padrino, Graduate Student

Pushpendra Singh, Department of Mechanical Engineering, New Jersey Institute of Technology, Newark, New Jersey

Flavia Viana, Research Associate

Jing Wang, Research Associate

Haoping Yang, Graduate Student