The fluid approximation is essential for describing a huge range of physical problems. Certain phenomena - superfluids being a key example - need multiple, coupled, inter-penetrating fluids to describe the important effects. The implications of these effects in astrophysics, once relativity is included, are still being worked out, but appear crucial for understanding neutron star dynamics.
We are studying the nonlinear effects in coupled relativistic inter-penetrating fluids. Even at the linear level there are instabilities that can explain certain features of pulsar glitches. The strong coupling regime of this instability, and more complex non-ideal couplings, are needed to produce quantitative predictions that can be compared with observations. This project studies the nonlinear couplings via numerical simulations, looking at the growth and saturation of these instabilities.
Algorithms and computational methods: Finite differences