Patent ID: 7478023

Claim:
A computer-implemented method of designing ink-jet print heads by simulating and analyzing viscoelastic fluid flow through, and ejection from, a channel having a boundary between a first fluid that flows through the channel and a second fluid, the method comprising: (a) performing finite difference analysis to solve, equations governing the viscoelastic flow of the first fluid through the channel, including viscoelastic stress equations, the finite difference analysis being performed by an algorithm that is explicit on an advection term, semi-implicit on a viscosity term, and implicit on a relaxation term, the finite difference analysis being performed to simulate the flow of the first fluid through, and ejection from, the channel; and (b) updating, periodically during the simulation, a level set function for the first and second fluids, wherein the level set function describes the position of the boundary between the first and second fluids, and the evolution of the level set function over time describes the shape and position of boundary as the first fluid is ejected from the channel; and (c) designing ink-jet print heads using the results of the simulation of the viscoelastic fluid flow.