Membranes and Complex Interfaces
Membranes play an important role in many biological processes, particularly at a cellular level. Processes such as desalination and
catalysis also involve membranes and complex interfaces. Understanding the complex interplay between a fluid and one of these interfaces
requires an accurate representation of thermal fluctuations at the mesoscale, such as that given by fluctuating hydrodynamics or DSMC.
A fluid in a non-equilibrium state exhibits long-ranged correlations of its hydrodynamic fluctuations. In this project,
we examine the effect of a transpiration interface on these correlations -- specifically, we consider a dilute gas in a domain
bisected by the interface. The system is held in a non-equilibrium steady state by using isothermal walls to impose a temperature
gradient. The gas is simulated using both direct simulation Monte Carlo (DSMC) and fluctuating hydrodynamics (FHD). For the FHD
simulations two models are developed for the interface based on master equation and Langevin approaches. For appropriate simulation
parameters, good agreement is observed between DSMC and FHD results with the latter showing a significant advantage in computational
speed. For each approach we quantify the effects of transpiration on long-ranged correlations in the hydrodynamic variables.