# Comparing Theory and Simulation for Thermo-osmosis

## TL;DR

This paper presents a numerical comparison of three methods to calculate thermo-osmotic slip in an ideal gas model, confirming the theoretical predictions and demonstrating consistency among the approaches.

## Contribution

It introduces and compares three numerical methods for calculating thermo-osmotic slip, validating the theoretical model with simulation results.

## Key findings

- Numerical results are mutually consistent.
- Results agree with theoretical predictions.
- Hydrodynamics and thermodynamics are locally valid.

## Abstract

We report a numerical study of thermo-osmotic slip, i.e. the particle flux induced by a thermal gradient along a solid-fluid interface. To facilitate comparison with theory, we consider a model of an ideal but viscous gas. We compare three numerical routes to obtain the slip coefficient: 1. by using the Onsager reciprocity relations 2. by using the appropriate Green-Kubo relation 3. via the excess enthalpy. The numerical results are found to be mutually consistent, and to agree with the theoretical prediction based on the assumption that hydrodynamics and thermodynamics are locally valid.