Hamiltonian transformation to compute Thermo-osmotic Forces

Abstract

If a thermal gradient is applied along a fluid-solid interface, the fluid experiences a thermo-osmotic force. In steady state this force is balanced by the gradient of the shear stress. Surprisingly, there appears to be no unique microscopic expression that can be used for computing the magnitude of the thermo-osmotic force. Here we report how, by treating the mass $M$ of the fluid particles as a tensor in the Hamiltonian, we can eliminate the balancing shear force in a non-equilibrium simulation and therefore compute the thermo-osmotic force at simple solid-fluid interfaces. We compare the non-equilibrium force measurement with estimates of the thermo-osmotic force based on computing gradients of the stress tensor. We find that the thermo-osmotic force as measured in our simulations cannot be derived from the most common microscopic definitions of the stress tensor.

5 pages, 2 figures

References in corpus (4)

• What controls thermo-osmosis? Molecular simulations show the critical role of interfacial hydrodynamics
• Molecular Simulation of Thermo-osmotic slip
• Pressure Gradients Fail to Predict Diffusio-Osmosis
• Microscopic Marangoni flows cannot be predicted on the basis of pressure gradients

Cited by in corpus (11)

• Osmosis, from molecular insights to large-scale applications
• Open-Boundary Hamiltonian adaptive resolution. From grand canonical to non-equilibrium molecular dynamics simulations
• Thermal forces from a microscopic perspective
• Thermo-osmosis in charged nanochannels: effects of surface charge and ionic strength
• Fast and Versatile Thermo-osmotic Flows with a Pinch of Salt
• Complex coupling between surface charge and thermo-osmotic phenomena
• Comparing Theory and Simulation for Thermo-osmosis
• Studying polymer diffusiophoresis with Non-Equilibrium Molecular Dynamics
• Relative Resolution: A Computationally Efficient Implementation in LAMMPS
• Relative Resolution: An Analysis with the Kullback-Leibler Entropy
• Fluid flow at interfaces driven by thermal gradients