Editing Computational fluid dynamics (section)

===Two-phase flow===

[[File:Bubble-rising.jpg|thumb|right|Simulation of bubble horde using [[volume of fluid method]]]]

The modeling of [[two-phase flow]] is still under development. Different methods have been proposed, including the [[Volume of fluid method]], the [[level-set method]] and [[front tracking]].<ref>{{cite journal |last1=Hirt |first1=C.W |last2=Nichols |first2=B.D |title=Volume of fluid (VOF) method for the dynamics of free boundaries |journal=Journal of Computational Physics |date=January 1981 |volume=39 |issue=1 |pages=201–225 |doi=10.1016/0021-9991(81)90145-5 |bibcode=1981JCoPh..39..201H }}</ref><ref>{{cite journal |last1=Unverdi |first1=Salih Ozen |last2=Tryggvason |first2=Grétar |title=A front-tracking method for viscous, incompressible, multi-fluid flows |journal=Journal of Computational Physics |date=May 1992 |volume=100 |issue=1 |pages=25–37 |doi=10.1016/0021-9991(92)90307-K |bibcode=1992JCoPh.100...25U |hdl=2027.42/30059 |hdl-access=free }}</ref>  These methods often involve a tradeoff between maintaining a sharp interface or conserving mass {{According to whom|date=November 2010}}.  This is crucial since the evaluation of the density, viscosity and surface tension is based on the values averaged over the interface.{{Citation needed|date=November 2010}}