Simulation of concentrated polymers in flow using a fluctuating field theory

In the flow of concentrated polymer systems, interactions among the polymers can couple with elasticity to change the rheology and flow instabilities. Simulations using continuum field theories are useful because of the high polymer concentration. We have used a fluctuating field theory called a stochastic kinetic theory, which is a relatively new approach for simulating nonequilibrium situations using field equations. Although it is coarse-grained relative to equilibrium polymer field theory, this approach naturally applies to nonequilibrium situations. It also provides more detail than present in two-fluid models. This new method is particularly important for systems in which fluctuations lead to structure formation or instabilities. In this talk, we will introduce the application of stochastic kinetic theories to concentrated polymers. We will quantify the accuracy of the numerical method and show how it can be used to examine structure formation and instabilities in flow.