From predicting sloshing in the Space Shuttle Tank in the mid-eighties to the design of microfluidic devices for today’s bio lab on a chip, CFDRC scientists and engineers have developed advanced models of systems with liquid interfaces. This expertise extends from the micro scale where capillary effects dominate, up to large scales, where momentum and gravity are the key effects. This expertise also includes the coupling of free surface phenomena with other physical effects such as mixing, phase-change, chemistry, electrodynamics, and fluid structure interaction.

Physical Models for Free Surfaces:

Volume of Fluid:
Free surfaces are modeled using an advanced Volume of Surface (VOF) technique in the context of a fully three-dimensional Navier Stokes solver.

Physical effects modeled include:

• Hydrodynamics with:

Complex free surface shapes
Surface Tension (with dynamic contact angles)
Capillary and Marangoni effects
Interaction with structures
Newtonian/Non-Newtonian Viscosity
Gravity
• Thermal Transport
  
• Chemistry
  
• Phase Changes

Hele Shaw:
Free surfaces in narrow gaps can be modeled using the more efficient, two and a half dimensional, Hele-Shaw model, including capillary effects

Predicted drag on a Naval vessel



Capillary flow with reaction
( N2 + O2 → 2NO )



Inkjet dynamics

Flooding in a watershed

Spray and sloshing